Fix Missed Updates Over Multiple Syncs

[dmosorast]

In this commit, I added a lookback window to engagements. There's another case where this same sort of thing can happen due to the way the companies API endpoint works (same as engagements, e.g., no sorting, no query-by-updated-at, etc.).

However, depending on the length of each tap-run, the existing pattern won't work across multiple runs, since it doesn't save any state until the end of the stream's sync.

The Solution Presented Here
The original pattern was to calculate a lookback window consisting of the end - start of the most recent sync. However, this PR modifies that to forcing the bookmark to be the min(current_sync_start, max_bk_seen) at the end of a sync, and saving current_sync_start into the state.

This is equivalent, and because current_sync_start is present in the state, it works across multiple interrupted invocations of the tap, so it should be more resilient to failure.