Support java.toolchain.languageVersion detection in build.gradle files

[rarkins]

Describe the proposed change(s).

Related discussion: #31987

Example from a build.gradle.kts file:

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(22)
    }
}

Ideally this would be used as part of

renovate/lib/modules/manager/gradle-wrapper/utils.ts

Lines 84 to 104 in f2d9a6a

	export async function getJvmConfiguration(
	gradlewFile: string,
	): Promise<string | null> {
	const daemonJvmFile = join(
	dirname(gradlewFile),
	'gradle/gradle-daemon-jvm.properties',
	);
	const daemonJvm = await readLocalFile(daemonJvmFile, 'utf8');
	if (daemonJvm) {
	const TOOLCHAIN_VERSION_REGEX = regEx(
	'^(?:toolchainVersion\\s*=\\s*)(?<version>\\d+)$',
	'm',
	);
	const toolChainMatch = TOOLCHAIN_VERSION_REGEX.exec(daemonJvm);
	if (toolChainMatch?.groups) {
	return toolChainMatch.groups.version;
	}
	}
	return null;
	}