The `TemplateTypeChecker.overrideComponentTemplate` operation was originally
conceived as a "fast path" for the Language Service to react to a template
change without needing to go through a full incremental compilation step. It
served this purpose until the previous commit, which switches the LS to use
the new resource-only incremental change operation provided by `NgCompiler`.
`overrideComponentTemplate` is now no longer utilized, and is known to have
several hard-to-overcome issues that prevent it from being useful in any
other situations. As such, this commit removes it entirely.
PR Close#40585
a3b0864428