fix(instr-express): normalize paths with double slashes

[JamieDanielson]

Which problem is this PR solving?

• closes Express instrumentation does not normalize paths (removing double slashes) #1547

Short description of the changes

• Add replace to remove duplicate slashes that may exist in defined routes
• Add unit test confirming route does not contain extra slash
• Add route to util serverWithMiddleware that contains double slashes, for use in test

Test results before the change:

+ expected - actual
-/double-slashes//:id
+/double-slashes/:id

[codecov]

Codecov Report

Merging #1995 (c90c654) into main (e24797e) will increase coverage by 5.08%.
Report is 2 commits behind head on main.
The diff coverage is n/a.

❗ Current head c90c654 differs from pull request most recent head 754361c. Consider uploading reports for the commit 754361c to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1995      +/-   ##
==========================================
+ Coverage   90.97%   96.06%   +5.08%     
==========================================
  Files         146       14     -132     
  Lines        7492      914    -6578     
  Branches     1502      199    -1303     
==========================================
- Hits         6816      878    -5938     
+ Misses        676       36     -640     

see 132 files with indirect coverage changes

[pichlermarc]

Looks good already, thanks for working on this 🙂
Just one question about the added test

[pichlermarc]

Looks good, thanks for working on this 🙂