build: configure Bazel to ignore packages/angular/build/node_modules

Although the `build` package is not present in this branch, the `node_modules` directory may persist when switching branches during a release, potentially causing the build to fail.

Author: alan-agius4

.bazelignore

@@ -1,6 +1,7 @@
 .git
 dist
 node_modules
+packages/angular/build/node_modules
 packages/angular/cli/node_modules
 packages/angular/create/node_modules
 packages/angular/pwa/node_modules