Fixed collecting base and overridden methods in ambiguous methods

[Damtev]

Description

Removed base methods in collecting ambiguous overloads that lead to the appearance of redundant and wrong casts.

Fixes #1641.

Type of Change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Manual Scenario

See the test in the issue.

Checklist (remove irrelevant options):

• The change followed the style guidelines of the UTBot project
• Self-review of the code is passed
• The change contains enough commentaries, particularly in hard-to-understand areas
• New documentation is provided or existed one is altered
• No new warnings