Drop unnecessary type arguments in the isolated declarations quick fix

[blickly]

Drops unnecessary type arguments in the isolated declarations quick fix by repeatedly trying to resolve a resulting reference type with a prefix of the full type arguments until finding the minimal number of arguments that work.

Fixes #58449

(I'm sure that the code at present isn't using the proper APIs, but I'd appreciate feedback)

[blickly]

OK, I switched to the more idiomatic way of creating a new AST node, rather than trying to mutate anything. PTAL

[blickly]

Any advice on who would make a good secondary reviewer?

[jakebailey]

Tested locally with main and it merges and passes cleanly.