Exit 1 with lint-intl failures

Co-authored-by: Jamie Kyle <113370520+jamiebuilds-signal@users.noreply.github.com>

build/intl-linter/linter.ts

@@ -136,6 +136,8 @@ async function lintMessages() {
 
   const jsonAst = parseJsonToAst(file);
 
+  let failed = false;
+
   assert(jsonAst.type === 'Object', 'Expected an object');
   for (const topProp of jsonAst.children) {
     if (topProp.key.value === 'smartling') {
@@ -202,8 +204,14 @@ async function lintMessages() {
       console.error(chalk`  {dim in ${key} is "}{red ${icuMessage}}{dim "}`);
       // eslint-disable-next-line no-console
       console.error();
+
+      failed = true;
     }
   }
+
+  if (failed) {
+    process.exit(1);
+  }
 }
 
 lintMessages().catch(error => {