Fixes #25278

So as it turns out, at using getNameOfSymbolAsWritten, which itself defers to declarationNameToString, which uses the verbatim original text of a module declaration's name and not the symbol's name (unless it has no node-based name) was an error. This meant ambient modules would be surrounded with single quotes if the original declaration used a single quoted string, rather than the double quotes we ensure we use internally (and therefore what we expect to match in ambientModuleSymbolRegex).

I've now changed symbolToTypeNode to use a much less brittle check for hasNonGlobalAugmentationExternalModuleSymbol on the symbol's declarations, and while I was at it, factored the module specifier parts out of getNameOfSymbolAsWritten (and reordered it so control flow worked better on it), since that's really not what getNameOfSymbolAsWritten is for.