Revert revert unwanted in dev branch

This reverts commit b05a8f7b54.

The release/10 branch received a revert that was applied after changes
from dev unwillingly where merged into it. But when merging release/10.0
back into dev, that revert was also applied to dev where the changes are
indeed wanted. So we revert the revert for dev.

Dangerfile

@@ -1,3 +1,22 @@
 # Fail if jasmine specs contain fdescribe or fit
 fail("jasmine fdescribe left in tests") if `grep --include '*.spec.ts' -rP 'fdescribe|fit' frontend/src/`.length > 1
 
+# Search for modified components not being made OnPush
+git.modified_files
+    .select { |path| path.include?('frontend') && path.end_with?('.ts') }
+    .each do |path|
+  lines = File.readlines(path)
+
+  # Ignore non component files
+  component_line = lines.grep(/@Component/)[0]
+  next unless component_line
+
+  # Check for missing onPush
+  unless lines.grep(/changeDetection:\s+ChangeDetectionStrategy.OnPush/).length > 0
+    warn(
+        "Please use `ChangeDetectionStrategy.OnPush` for this component",
+        file: path,
+        line: lines.index(component_line) || 0
+        )
+  end
+end