[Password Manager] Silence navigator.clipboard.writeText errors

Occasionally navigator.clipboard.writeText can fail with "Document not
focused" error. This causes test flakiness. To fix this error is
caught early.

Fixed: 1439197
Change-Id: I7b11133700eb46b0a59c327ff2b60bbf8d06c956
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4506696
Reviewed-by: Andrii Natiahlyi <natiahlyi@google.com>
Auto-Submit: Viktor Semeniuk <vsemeniuk@google.com>
Commit-Queue: Andrii Natiahlyi <natiahlyi@google.com>
Commit-Queue: Viktor Semeniuk <vsemeniuk@google.com>
Cr-Commit-Position: refs/heads/main@{#1139419}