Fix ts.transpileDeclaration having empty sourceMapText when declarationMap is true

[MichaelMitchell-at]

Fixes #59313

[MichaelMitchell-at]

I've verified this fixes the issue for my use case, but I'm not sure how to write a test for this. I didn't find any existing tests that I could use as a reference.

cc @weswigham

[MichaelMitchell-at]

This being set to undefined caused declarationMap to be set to undefined in options

TypeScript/src/services/transpile.ts

Lines 130 to 137 in f37482c

	for (const option of transpileOptionValueCompilerOptions) {
	// Do not set redundant config options if `verbatimModuleSyntax` was supplied.
	if (options.verbatimModuleSyntax && optionsRedundantWithVerbatimModuleSyntax.has(option.name)) {
	continue;
	}
	options[option.name] = option.transpileOptionValue;
	}

[MichaelMitchell-at]

Before we were passing true to forceDtsEmit, which caused this to evaluate to false:

TypeScript/src/compiler/emitter.ts

Line 907 in f37482c

sourceMap: !forceDtsEmit && compilerOptions.declarationMap,

though I'm not sure if this is actually the correct fix. Perhaps it would be to just remove !forceDtsEmit && from emitter.ts.

Changing emitOnlyDtsFiles to undefined actually doesn't seem to matter, at least with the configuration I tested with, which seems kind of surprising.

[MichaelMitchell-at]

Well, no permutation of what I said results in all the tests passing, so clearly not as easy of a fix as I hoped.

[sheetalkamat]

Closing in favor of #59337