bridge: drain each socket up to a fixed number

[deanlee]

The updated approach processes up to MAX_MESSAGES_PER_SOCKET before moving to the next one. This prevents any single socket from dominating processing and ensures a more balanced distribution of message handling, similar to what was done in loggerd.

resolve #32862 (comment):

@sshane: now PJ streaming looks rather choppy and sometimes skips a split second of data, can you take another look at this?

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