Remove always-incorrect error message about importing .ts extensions

[andrewbranch]

Fixes #52320

Hilariously, after recent resolution changes by me and Wesley, the message

An import path cannot end with a '{0}' extension. Consider importing '{1}' instead.

only ever showed up when its suggestion in {1} does not exist. If it did exist, you would have gotten the message

An import path can only end with a '{0}' extension when 'allowImportingTsExtensions' is enabled.

So, the error message was literally always wrong, not just when allowImportingTsExtensions was enabled 🙃

[microsoft-github-policy-service]

Thanks for the PR! It looks like you've changed the TSServer protocol in some way. Please ensure that any changes here don't break consumers of the current TSServer API. For some extra review, we'll ping @sheetalkamat, @mjbvz, @zkat, and @joj for you. Feel free to loop in other consumers/maintainers if necessary

[sheetalkamat]

why is this correct error message when the file doesnt exist ?

[andrewbranch]

Oh, I actually didn’t look close enough at this one. This is weird; I think it’s only supposed to show up for non-relative names.

[andrewbranch]

Hm, this message just always comes up in classic, probably because classic is terrible and nobody should use it. It doesn’t make a ton of sense for relative imports, but honestly if someone is on classic it probably is a mistake, so I think we should leave it.