Refactoring rename of PipKeepClearAlgorithm

Renaming PipKeepClearAlgorithm to PipKeepClearAlgorithmInterface,
to make an easier transition of moving TvPipKeepClearAlgorithm into
shared PiP codebase.

Test: n/a, refactoring code with IntelliJ, renaming interface
Bug: 265207213
Merged-In: Ic16cd7eefa034259d5d7f141f2817eb4f7b597ec
Change-Id: I2f15dc2d7912fa1df60c6211a8499cd7a222e59e