[py] Correct frame switching expected condition

During PRs a conflict didn't get landed properly. This should fix it.

Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/SeleniumHQ/selenium
Cr-Mirrored-Commit: 8d9ea942c3d1ca576747ec110f091ffdef481a6b
1 file changed