[6.14.z] session name for bookmarks

[Satellite-QE]

Cherrypick of PR: #14242

Problem Statement

name.lower wasn't always equal with session name, also removed some dead code and unused params

Solution

making the session name explicit in constants

[Satellite-QE]

trigger: test-robottelo
pytest: tests/foreman/ui/test_bookmarks.py -k test_positive_create_bookmark_public

[Satellite-QE]

PRT Result

Build Number: 6011
Build Status: UNSTABLE
PRT Comment: pytest tests/foreman/ui/test_bookmarks.py -k test_positive_create_bookmark_public --external-logging
Test Result : = 6 failed, 30 passed, 1 skipped, 156 deselected, 89 warnings, 2 errors in 3864.20s (1:04:24) =

[pondrejk]

the 6 remaining failures are not due to the original problem, some more work on the airgun side is needed for those