Removed legacy code from HotChocolate.Language

[glen-84]

Summary of the changes (Less than 80 chars)

• Removed legacy code from HotChocolate.Language.

[codecov]

Codecov Report

Attention: Patch coverage is 80.76923% with 20 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@99c61fe). Learn more about missing BASE report.

Files	Patch %	Lines
.../CodeGeneration/Analyzers/EnumTypeUsageAnalyzer.cs	77.27%	10 Missing ⚠️
...ypes/Utilities/ObjectValueToDictionaryConverter.cs	86.95%	6 Missing ⚠️
...neration/Analyzers/InputObjectTypeUsageAnalyzer.cs	71.42%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7193   +/-   ##
=======================================
  Coverage        ?   72.29%           
=======================================
  Files           ?     2619           
  Lines           ?   131485           
  Branches        ?        0           
=======================================
  Hits            ?    95055           
  Misses          ?    36430           
  Partials        ?        0           

Flag	Coverage Δ
unittests	72.29% <80.76%> (?)

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