Automatically disable key rotation checks for file_key_management plugin

There have been several bug reports about how the background encryption threads can use a lot of CPU. Prior analysis suggested those this is primarily caused by the operations that check for key rotation. As part of MDEV-11738, the innodb_encryption_rotate_key_age system variable's special 0 value was added to disable these checks, and this does seem to help most users.

The default value of innodb_encryption_rotate_key_age is 1, so key rotation checks will be enabled by default. The problem is that many encryption users will be using {file_key_management}} plugin, which doesn't even support key rotations. Many of these users are not aware that they should set innodb_encryption_rotate_key_age to 0, so their background threads will be using more CPU than is necessary.

Would it be possible to automatically disable key rotation checks for file_key_management plugin (and maybe other plugins that don't support key rotation)?