wallet - UI fixes

[thedoublejay]

What kind of PR is this?:

/kind fix

What this PR does / why we need it:

1. SectionTitle for CommunityScreen
2. Update button label for remove liquidity
3. Prevent NaN for Convert screen
4. Don't show negative values for Convert Screen

Which issue(s) does this PR fixes?:

Fixes #387

Additional comments?:

[codeclimate]

Code Climate has analyzed commit 6c1dc43 and detected 0 issues on this pull request.

View more on Code Climate.

[codecov]

Codecov Report

Merging #391 (6c1dc43) into main (3b6b51f) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #391      +/-   ##
==========================================
- Coverage   87.95%   87.93%   -0.03%     
==========================================
  Files          92       92              
  Lines        1387     1384       -3     
  Branches      207      206       -1     
==========================================
- Hits         1220     1217       -3     
  Misses        166      166              
  Partials        1        1              

Impacted Files	Coverage Δ
...vigator/screens/Balances/screens/ReceiveScreen.tsx	100.00% <ø> (ø)
...ns/AppNavigator/screens/Dex/DexRemoveLiquidity.tsx	94.11% <ø> (ø)
...gator/screens/Settings/screens/CommunityScreen.tsx	100.00% <ø> (ø)
...ns/AppNavigator/screens/Balances/ConvertScreen.tsx	96.00% <100.00%> (ø)
...reens/AppNavigator/screens/Dex/DexAddLiquidity.tsx	95.52% <100.00%> (-0.20%)	⬇️

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[netlify]

✔️ Deploy Preview for defi-wallet ready!

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[defichain-bot]

Build preview for DeFi Wallet is ready!

Built with commit 464dede

https://expo.io/@defichain/wallet?release-channel=pr-preview-391

[cypress]

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Test summary

116 • 0 • 0 • 0

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Run details

Project	wallet
Status	Passed
Commit	464dede ℹ️
Started	Aug 2, 2021 5:31 AM
Ended	Aug 2, 2021 5:46 AM
Duration	14:25 💡
OS	Linux Ubuntu - 20.04
Browser	Chrome 92

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