Erase flash from dashboard

**Describe the problem you have/What new integration you would like**
It would be great to have the ability to erase the flash of an ESP directly through the UI using webserial.

**Please describe your use case for this integration and alternatives you've tried:**
While testing several stuff over time, I have a few ESP that are programmed with the same code as running ones.
When connecting such a spare ESP, it would use the same mDNS name will try to connect to Home Assistant which is not wanted and could conflict with the real integration.
Having the ablility to erase the flash directly from the dashboard would eliminate the need to install Python and esptool.

**Additional context**
If webserial is a limitation, I would suggest to add a "Erase Flash" button on ESPHome Flasher.

No files, tests, or implementation entry points are named. Start by investigating the dashboard's webserial capabilities and the ESPHome Flasher alternative, then determine whether either can erase an ESP flash. Done means a user can trigger flash erasure from the dashboard or the proposed flasher and avoid the spare device reconnecting to Home Assistant.

Written by the indexing model from the issue text.