fix(performance): decrease nemesis test duration

[juliayakovlev]

The maximum duration that we got for the perf-regression-latency-650gb-with-nemesis test is 12 hours. Now test duration is 50 hours. It's too much. Decrease it to 14 hours.

Testing

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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)

[soyacz]

We used to have mgmt repair lasting 6h - is this gone? or we still fit in 12h window with it?

[juliayakovlev]

We used to have mgmt repair lasting 6h - is this gone? or we still fit in 12h window with it?

Long mgmt repair was fix in the new manager version. Now the longest is about 2.5h.
As far as I found, 12 it was maximum test duration. So I prolonged it to 14 just to be safe