Allow template strings (with no interpolated expressions) to start off with literal types

[DanielRosenwasser]

I can't find the original issue (if there is one).

const c: "hello" = `hello`

Expected: No error.
Actual: Type 'string' is not assignable to type '"hello"'.

We should just allow people to use NoSubstitutionTemplates the way that they're allowed to use regular strings.

[ericbf]

This should also cover using NoSubstitutionTemplates as literal types as in #18109

[ericbf]

Is there any progress being made on this?

@andy-ms the PR that referenced this issue didn't completely resolve the cases covered by using NoSubstitutionTemplates as literal types.