[CI] Increase IBD timeout
Summary:
IBD tends to timeout since the split, bump the value to 8h for all
configs.
Test Plan:
See IBD duration and logs on CI and check the value is appropriated.
Reviewers: #bitcoin_abc, majcosta
Reviewed By: #bitcoin_abc, majcosta
Differential Revision: https://reviews.bitcoinabc.org/D8585