Remove circularity fallback deferral in getConditionalType

[weswigham]

Per commentary in #30443, this reverts the code change in #30375, but keeps the new test.

[weswigham]

@typescript-bot run dt

[typescript-bot]

Heya @weswigham, I've started to run the Definitely Typed test suite on this PR at c6df72c. You can monitor the build here. It should now contribute to this PR's status checks.

[weswigham]

DT failure is in ramda:

Error in ramda
Error: /home/vsts/work/1/s/dtslint-runner/DefinitelyTyped/types/ramda/ramda-tests.ts:970:26
ERROR: 970:26  expect  TypeScript@local compile error: 
Argument of type '<T>(obj: Record<"id", T>) => T' is not assignable to parameter of type '(a: Record<"id", T>) => string'.
  Type 'T' is not assignable to type 'string'.

    at /home/vsts/work/1/s/dtslint-runner/node_modules/dtslint/bin/index.js:210:19
    at Generator.next (<anonymous>)
    at fulfilled (/home/vsts/work/1/s/dtslint-runner/node_modules/dtslint/bin/index.js:5:58)
The following packages had errors: ramda
FAILED

It's the const a2 = R.indexBy(R.prop("id"))(list); - which looks like the last error left in ramda after today's fix (which I think the author already said might be due to some incorrect types in ramda, rather than a fault on our part - I haven't looked into this one, though).

In any case, not the fault of reverting this, so I'm going to merge this.