realtek: Add Conflicts and Replaces against firmware-realtek-rtl8723cs-bt

Since version 20240909-1, firmware-realtek includes RTL8723CS Bluetooth config and firmware files that were already packaged in firmware-realtek-rtl8723cs-bt. The versions of these files differ between the two packages, but the maintainer of the latter is happy for us to take them over.

Add Conflicts and Replaces without versions, since there are no other firmware files in firmware-realtek-rtl8723cs-bt and it will go away completely.

Since these files are moving between packages in the same release cycle as a move from /lib/firmware to /usr/lib/firmware, also enable usrmovemitigation for them.

Closes: #1084791