Only use `frame_types` if delivered during enter

The `open_history_client()` provider endpoint can *optionally*
deliver a `frame_types: dict[int, pendulum.Duration]` subsection in its
`config: dict[str, dict]` (as was implemented with the `ib` backend).
This allows the `tsp` backfilling machinery to use this "recommended
frame duration" to subtract from the `last_start_dt` any time a `NoData`
gap is signalled by the `get_hist()` call allowing gaps to be ignored
safely without missing history by knowing the next earliest dt we can
query from using the `end_dt`. However, currently all crypto$ providers
haven't implemented this feat yet..

As such only try to use the `frame_types` feature if provided when
handling `NoData` conditions inside `tsp.start_backfill()` and otherwise
raise as normal.

piker/tsp/__init__.py

@@ -434,21 +434,32 @@ async def start_backfill(
                 # - some other unknown error (ib blocking the
                 #   history bc they don't want you seeing how they
                 #   cucked all the tinas..)
-                if dur := frame_types.get(timeframe):
-                    # decrement by a frame's worth of duration and
-                    # retry a few times.
-                    last_start_dt.subtract(
+                if (
+                    frame_types
+                    and
+                    (dur := frame_types.get(timeframe))
+                ):
+                    # decrement by a duration's (frame) worth of time
+                    # as maybe indicated by the backend to see if we
+                    # can get older data before this possible
+                    # "history gap".
+                    orig_last_start_dt = last_start_dt
+                    last_start_dt = last_start_dt.subtract(
                         seconds=dur.total_seconds()
                     )
                     log.warning(
                         f'{mod.name} -> EMPTY FRAME for end_dt?\n'
                         f'tf@fqme: {timeframe}@{mkt.fqme}\n'
-                        'bf_until <- last_start_dt:\n'
-                        f'{backfill_until_dt} <- {last_start_dt}\n'
-                        f'Decrementing `end_dt` by {dur} and retry..\n'
+                        f'Decrementing `end_dt` by {dur} and retry..\n\n'
+
+                        f'orig_last_start_dt: {orig_last_start_dt}\n'
+                        f'dur subtracted last_start_dt: {last_start_dt}\n'
+                        f'bf_until: {backfill_until_dt}\n'
                     )
                     continue
 
+                raise
+
             # broker says there never was or is no more history to pull
             except DataUnavailable:
                 log.warning(