[CDF-26133]  🪦Prep v0.7 - remove cdf dump data (#2237)

# Description

**Merge after** #2236

Remove dump data. Note this will only occur if the `v0.7` alpha flag is
enabled.

I also added a `v0.8` alpha flag such that remember to delete the
command entirely in the `v0.8` release.

## Bump

- [x] Patch
- [ ] Skip

## Changelog

### Removed

- [alpha] `cdf dump assets/timeseries/event/files-metadata` commands.
These have been replaced by `cdf data download
assets/timeseries/events/files`. Note this removal only occurs if the
alpha flag `v07` is set to `true`.
