Improve error output of wasm-builder when wasm ins't installed (#7105)

This improves the error message of wasm-builder when the wasm toolchain
isn't installed. Currently we print that the wasm toolchain is not
installed, but the actual problem is that there is a bug in the
packaging in rust. This will now be much easier to debug, by printing
the full error message of the compiler.

substrate/utils/wasm-builder/src/wasm_project.rs

@@ -449,7 +449,7 @@ fn build_project(project: &Path, default_rustflags: &str) {
 		// We don't want to call ourselves recursively
 		.env(crate::SKIP_BUILD_ENV, "");
 
-	if env::var(crate::WASM_BUILD_NO_COLOR).is_err() {
+	if super::color_output_enabled() {
 		build_cmd.arg("--color=always");
 	}