Use the compiler options as a backup for finding compiler options from inside the param handling code

[orta]

Prior versions of the playground have just relied on a big 'defaults dump' to use as a reference about what compiler options are recognized from the url query. This works well enough _if you are completely on top of all compiler options and updating the website, but I've been doing a lot of work outside of the website and it's a bad call to rely on that in the future.

TypeScript-Website/packages/sandbox/src/compilerOptions.ts

Lines 10 to 17 in 66d7d8b

	export function getDefaultSandboxCompilerOptions(config: SandboxConfig, monaco: Monaco) {
	const useJavaScript = config.filetype === "js"
	const settings: CompilerOptions = {
	noImplicitAny: true,
	strictNullChecks: !useJavaScript,
	strictFunctionTypes: true,
	strictPropertyInitialization: true,
	strictBindCallApply: true,

This PR re-uses the same idea as #1735 which is that we have the TS compiler in the runtime, so we should use that to validate whether a param a legit compiler flag even if it's not available in playground the defaults.

[orta]

and includes a fix for #1919