delete_snapshot does not delete keys properly when snapshot has more than one symbol in it

[poodlewars]

Describe the bug

delete_snapshot only works on a single symbol in the snapshot. The data keys for any others are not deleted properly.

This is because recurse_index_keys assumes that all the index keys are for the same symbol, which is not the case when it is called by delete_snapshot.

Steps/Code to Reproduce

See https://github.com/man-group/ArcticDB/commit/113a6a4d60267c16c87e870e3fcbb88bab4d5fc8

Expected Results

OS, Python Version and ArcticDB Version

Backend storage used

No response

Additional Context

No response