[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