Move LB call in overriden method for MatchingMergeRequest to Core
What does this MR do?
Small extraction of big MR (!60894 (diffs))
This is background work, and should not impact as currently it is behind a environment variable (ENABLE_LOAD_BALANCING_FOR_FOSS
)
Therefore it should not affect FOSS, nor EE
Related issue: #327902 (closed)