[Backport 6.2] fix(nemesis): filter raft-topology errors when starting/stopping nodes

[mergify]

raft is generating the following errors:
raft_topology - topology change coordinator fiber got error std::runtime_error
when one of the nodes is stopped, it was decided we can safely ignore those errors

fixes: #9031

PR pre-checks (self review)

• I added the relevant backport labels
• I didn't leave commented-out/debugging code

Reminders

• Add New configuration option and document them (in sdcm/sct_config.py)
• Add unit tests to cover my changes (under unit-test/ folder)
• Update the Readme/doc folder relevant to this change (if needed)

(cherry picked from commit 2093714)

Parent PR: #9580