Epic: tsp, TCGC common layer adoption enhancements

[haolingdong-msft]

Remaining issues that should be done after TCGC supports, TCGC dependency issue is listed in each issue.

Sdkpackage adoption issue: #2665
SdkType adoption issue: #2564

Tasks

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1. tsp, support TCGC added endpoint together with user defined endpoint for one client #2912
   +0
   
2. tsp, support filtering API versions #2913
   1 of 1
   +0
   
3. tsp, TCGC adoption, support parameter onClient #2920
   1 of 1
   +0
   
4. tsp, TCGC adoption, Handle optional content-type #2930
   1 of 3
   +0
   
5. TSP, TCGC common layer, use TCGC returned usage #2729
   2 of 2
   +0
   
6. TSP, TCGC common layer, use TCGC returned access #2728
   0 of 1
   +0
   
7. TSP, TCGC adoption, use TCGC returned flag to check whether a sdkMethod is overloaded #2932
   +0
   
8. http-client-java, emitter, TCGC integration, deprecate TCGC's description and details microsoft/typespec#4394
   emitter:client:java +1
   
9. TSP, TCGC adoption, not change enum type to string type for client parameter #2974
   +0
   
10. TSP, TCGC adoption, use SdkServiceMethod rather than SdkHttpOperation to generate method signature #2984
    +0

TCGC dependencies

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1. [TCGC] Could TCGC provide an easier way to map from SdkMethodParameter to SdkPathParameter | SdkQueryParameter | SdkHeaderParameter | SdkBodyParameter? typespec-azure#1441
   design:needed feature lib:tcgc +3
   
2. [TCGC] api-version parameter should not be onClient===true if the server is non-versioned typespec-azure#1391
   bug lib:tcgc +2
   
3. [TCGC][Bug] TCGC added content-type header should be optional if request body is optional typespec-azure#1259
   lib:tcgc +1
   

TCGC dependencies for adopting access and usage

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1. [TCGC] [Bug] TCGC should return usage as 0 for model when it is only used in protocol method's response body typespec-azure#1748
   lib:tcgc +1
   
2. [TCGC] [Bug] response/request header schema should not be generated typespec-azure#1749
   lib:tcgc +1
3. [TCGC][LRO] LRO initial response model should not be generated typespec-azure#1750
   lib:tcgc +1
   
4. [Bug][TCGC] TCGC introduces anonymous model for LRO operation typespec-azure#1538
   lib:azure-core +1
   
5. [TCGC] provide access and usage for SdkConstantType typespec-azure#1747
   lib:tcgc +1
6. [TCGC] [LRO] lroMetadata.pollingStep.responseBody.usage is not correct when polling operation is defined in different namespace typespec-azure#1752
   lib:tcgc +1
   

[haolingdong-msft]

TCGC usage and access case study: https://gist.github.com/haolingdong-msft/df3f25a048baf83d8fabf5206aacc7db
TCGC usage and access case study for spread cases: https://gist.github.com/haolingdong-msft/2d941f452551a6f96e141adbc38ac483