[feat] Honor a specified NDK version, if set

[NyaomiDEV]

Describe the problem

Latest Tauri versions try to build using the latest NDK which is installed in the system - not the specified NDK through the NDK_HOME variable. This means it's impossible to reproduce a build within build systems, and this adds unnecessary friction should developers want their apps to be reproducible by others (such as the guys over at F-Droid / IzzyOnDroid.)

Describe the solution you'd like

If NDK_HOME is set, Tauri should honor that instead of trying to get the latest NDK from $ANDROID_HOME/ndk.

Ref:

tauri/crates/tauri-cli/src/mobile/android/mod.rs

Lines 347 to 365 in 3257612

	// re-evaluate ANDROID_HOME
	let android_home = std::env::var_os("ANDROID_HOME")
	.or_else(|| std::env::var_os("ANDROID_SDK_ROOT"))
	.map(PathBuf::from)
	.context("Failed to locate Android SDK")?;
	let mut installed_ndks = read_dir(android_home.join("ndk"))
	.map(|dir| {
	dir
	.into_iter()
	.flat_map(|e| e.ok().map(|e| e.path()))
	.collect::<Vec<_>>()
	})
	.unwrap_or_default();
	installed_ndks.sort();
	if let Some(ndk) = installed_ndks.last() {
	log::info!("Using installed NDK: {}", ndk.display());
	std::env::set_var("NDK_HOME", ndk);
	} else if non_interactive {

Alternatives considered

No response

Additional context

No response