Filter out the range of index before the index is visible

Feature Request

Is your feature request related to a problem? Please describe:

The process of add index is firstly writing index for existed rows and then make the index visible. For now, we subscribe to all regions in the range of table. Thus all operations for writing index for existed rows will be sent to ticdc from tikv as key/value operations, which are duplicated with add index in downstream.

Describe the feature you'd like:

If we do not subscribe to the range of an invisible index, then unnecessary data flow during adding an index can be avoided.