Fix CA1853 firing when another dictionary used for ContainsKey

[louis-z]

Only if ContainsKey() & Remove() are invoked on the exact same field, property, parameter or local variable will the CA1853 rule now kick in.

Note that, as a result, if the methods are called using syntactically different but semantically equal references (e.g. 2 variables that have reference equality), the rule will not trigger.

Fixes #6377

[codecov]

Codecov Report

Merging #6516 (2bc8408) into main (c6352bf) will decrease coverage by 0.01%.
The diff coverage is 91.80%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6516      +/-   ##
==========================================
- Coverage   96.41%   96.41%   -0.01%     
==========================================
  Files        1371     1371              
  Lines      319166   319224      +58     
  Branches    10270    10271       +1     
==========================================
+ Hits       307732   307784      +52     
- Misses       8979     8981       +2     
- Partials     2455     2459       +4