Add templateLock attribute to core/cover.

[Locheed]

What problem does this address?

core/column and core/group did get the templateLock attribute. However, it would be good to have this option with other blocks too. e.g. core/cover. This block is awesome but cannot be really used on the client's site because it cannot be locked.

This however does work as a top-level block with inheriting templateLock from InnerBlocks. But now there does not have inheritance any more with core/columns > core/column > core/cover.

#26128

What is your proposed solution?

Add possibility to use the templateLock attribute directly with core/cover.

[paaljoachim]

General locking is being worked on these days.
Here is a Locking tracking issue:
On Locking and TemplateLocking
#29864

[Mamaduka]

Fixed via #29916.