cli: avoid running prepare a second time in ci (microsoft#184558)

Author: connor4312

build/azure-pipelines/cli/prepare.js

@@ -38,6 +38,7 @@ const makeQualityMap = <T>(m: (productJson: any, quality: string) => T): Record<
  */
 const setLauncherEnvironmentVars = () => {
 	const vars = new Map([
+		['VSCODE_CLI_ALREADY_PREPARED', 'true'],
 		['VSCODE_CLI_REMOTE_LICENSE_TEXT', product.serverLicense?.join('\\n')],
 		['VSCODE_CLI_REMOTE_LICENSE_PROMPT', product.serverLicensePrompt],
 		['VSCODE_CLI_AI_KEY', product.aiConfig?.cliKey],

build/azure-pipelines/cli/prepare.ts

@@ -20,7 +20,7 @@ fn main() {
 
 fn apply_build_environment_variables() {
 	// only do this for local, debug builds
-	if env::var("PROFILE").unwrap() != "debug" {
+	if env::var("PROFILE").unwrap() != "debug" || env::var("VSCODE_CLI_ALREADY_PREPARED").is_ok() {
 		return;
 	}