Export envVarToBoolean helper

[maorleger]

In order to provide a consistent experience integrating with boolean environment variables we should export a envVarToBoolean helper modeled after the one exported in

azure-sdk-for-js/sdk/instrumentation/opentelemetry-instrumentation-azure-sdk/src/configuration.ts

Lines 26 to 39 in 6a8dd2c

	export function envVarToBoolean(key: KnownEnvironmentKey): boolean {
	if (!environmentCache.has(key)) {
	loadEnvironmentVariable(key);
	}
	const value = (environmentCache.get(key) ?? "").toLowerCase();
	return value !== "false" && value !== "0" && Boolean(value);
	}
	function loadEnvironmentVariable(key: KnownEnvironmentKey): void {
	if (typeof process !== "undefined" && process.env) {
	const rawValue = process.env[key] ?? process.env[key.toLowerCase()];
	environmentCache.set(key, rawValue);
	}
	}

Notes:

• Ignore the cache section, it's not needed as node will cache the env vars anyway
• Allow any string, not just the known strings
• "false" and "0" should translate to boolean false

> Boolean("false")
false
> Boolean("0")
false

Original text from PR:

I am not sure if we export a "envVarToBoolean" helper, but if not I should make an issue to export one from core-util. This is probably fine for now? Up to you (and your team)!

Originally posted by @maorleger in #31160 (comment)