Resolve #3582892 "Batch title"

Closes #3582892

Adds an optional "Override batch progress title" field to each operation's configuration in the VBO bulk form field settings. This follows the same pattern as the existing "Override label" and "Override finish message" fields. When left empty, the existing default title (Performing @operation on selected entities.) is preserved as a fallback.

• Updates the action configuration form.
• Sets the batch title or uses the default in the batch setup.
• Adds the batch_title_override key to the module schema definitions.
• A simple test to verify the new config property translates to a batch title.