unusedStandaloneImports is a warning during dev #11812

Production builds will keep erroring with `unusedStandaloneImports` (so
CI will fail). But dev and test builds, will only emit a warning. This
make it easier to develop and add/remove components temporarily.

Author: PowerKiKi

angular.json

@@ -54,6 +54,7 @@
                     },
                     "configurations": {
                         "production": {
+                            "tsConfig": "client/tsconfig.app.prod.json",
                             "define": {
                                 "globalThis.__DEV__": "false"
                             },

client/tsconfig.app.prod.json

@@ -0,0 +1,10 @@
+{
+    "extends": "./tsconfig.app.json",
+    "angularCompilerOptions": {
+        "extendedDiagnostics": {
+            "checks": {
+                "unusedStandaloneImports": "error"
+            }
+        }
+    }
+}

tsconfig.json

@@ -28,7 +28,10 @@
         // Remove this when https://github.com/angular/angular/issues/37619 is fixed
         "strictSafeNavigationTypes": false,
         "extendedDiagnostics": {
-            "defaultCategory": "error"
+            "defaultCategory": "error",
+            "checks": {
+                "unusedStandaloneImports": "warning"
+            }
         }
     },
     // Otherwise, eslint parses our temp files and crashes, see https://github.com/typescript-eslint/typescript-eslint/issues/1192