fix: Prevent scheduling of windows with duplicate starting times (SC-13253)

[vbidin]

Addresses 3S issue #8

[shortcut-integration]

This pull request has been linked to Shortcut Story #13253: [mplv2] [audit-fix] Add check to avoid 2 windows with same starting time..

[github-actions]

| contracts/MapleTokenProxy.sol:MapleTokenProxy contract |                 |       |        |        |         |
|--------------------------------------------------------|-----------------|-------|--------|--------|---------|
| Deployment Cost                                        | Deployment Size |       |        |        |         |
| 457692                                                 | 2222            |       |        |        |         |
| Function Name                                          | min             | avg   | median | max    | # calls |
| addModule                                              | 12702           | 32431 | 32045  | 117545 | 35      |
| balanceOf                                              | 1226            | 3028  | 1226   | 7726   | 38      |
| burn                                                   | 1416            | 11459 | 10111  | 21344  | 7       |
| decimals                                               | 1023            | 1023  | 1023   | 1023   | 8       |
| globals                                                | 1154            | 2091  | 1154   | 7654   | 16      |
| governor                                               | 6438            | 6438  | 6438   | 6438   | 1       |
| implementation                                         | 1111            | 1111  | 1111   | 1111   | 2       |
| isModule                                               | 1194            | 1194  | 1194   | 1194   | 4       |
| mint                                                   | 1416            | 17147 | 12800  | 38400  | 7       |
| name                                                   | 1842            | 1842  | 1842   | 1842   | 1       |
| removeModule                                           | 12612           | 24429 | 23363  | 68037  | 13      |
| setImplementation                                      | 7392            | 38147 | 11875  | 95174  | 3       |
| symbol                                                 | 1929            | 1929  | 1929   | 1929   | 1       |
| totalSupply                                            | 1028            | 1916  | 1028   | 3028   | 9       |
| transfer                                               | 3684            | 23955 | 26384  | 30084  | 7       |
| contracts/RecapitalizationModule.sol:RecapitalizationModule contract |                 |       |        |       |         |
|----------------------------------------------------------------------|-----------------|-------|--------|-------|---------|
| Deployment Cost                                                      | Deployment Size |       |        |       |         |
| 1013506                                                              | 5246            |       |        |       |         |
| Function Name                                                        | min             | avg   | median | max   | # calls |
| claim                                                                | 21739           | 31954 | 28634  | 45490 | 3       |
| claimable                                                            | 1652            | 2985  | 1652   | 5652  | 3       |
| lastClaimedTimestamp                                                 | 379             | 379   | 379    | 379   | 7       |
| lastClaimedWindowId                                                  | 336             | 336   | 336    | 336   | 63      |
| lastScheduledWindowId                                                | 391             | 891   | 391    | 2391  | 4       |
| schedule                                                             | 56282           | 68300 | 71305  | 71305 | 5       |
| windows                                                              | 699             | 1090  | 699    | 2699  | 312     |

[github-actions]

LCOV of commit 70596c4 during CI #94

Summary coverage rate:
  lines......: 100.0% (87 of 87 lines)
  functions..: 100.0% (28 of 28 functions)
  branches...: no data found

Files changed coverage rate:
                                      |Lines       |Functions  |Branches    
  Filename                            |Rate     Num|Rate    Num|Rate     Num
  ==========================================================================
  contracts/RecapitalizationModule.sol| 100%     52| 100%    10|    -      0

[github-actions]

LCOV of commit c260e1e during CI #96

Summary coverage rate:
  lines......: 100.0% (87 of 87 lines)
  functions..: 100.0% (28 of 28 functions)
  branches...: no data found

Files changed coverage rate:
                                      |Lines       |Functions  |Branches    
  Filename                            |Rate     Num|Rate    Num|Rate     Num
  ==========================================================================
  contracts/RecapitalizationModule.sol| 100%     52| 100%    10|    -      0