[Bug][getAllOperations]: alias model is not calculated

[archerzz]

Describe the bug

• If a normal anonymous model is defined, it will be given a name in TCGC.
• If an anonymous model is defined through alias, it won't be given a name.

I found that usage of alias model is not calculated as well. It's always None.

To Reproduce
Try to compile the test case using getAllOperations branch: https://github.com/Azure/autorest.csharp/blob/31e7b662d82c01fa8e6725437c1daa2227a2aeb8/test/TestProjects/Spread-TypeSpec/Spread-TypeSpec.tsp#L97-L101

Expected behavior
Anonymous model defined by an alias should be calculated.

[iscai-msft]

we shouldn't be returning models that are aliases, so if anything we need to make sure that we're not returning aliases

[tadelesh]

we shouldn't be returning models that are aliases, so if anything we need to make sure that we're not returning aliases

Current getAllModels will return alias model. I don't remember clearly if it is because after compiling, we could not distinguish a model type is from model or alias definition.

[tadelesh]

follow up with tsp team to see how to separate them.

[tadelesh]

Folk the alias problem into another issue: #300

[tadelesh]

This issue is likely a usage calculation problem. Will investigate soon.

[iscai-msft]

closing in favor of #300