CTHUB - GER email validation

**Describe the task**
Users should get a warning when uploading the GER dataset if a cell in the `Email` column contains an invalid email. Users should be able to ignore this warning and proceed to the upload.

**Purpose**
Reduces the number of emails that will bounce because of incorrect spelling.

**Acceptance Criteria**
- [ ] Basic issues such as missing `@`, improper domain names such as `gmail.org` should be caught.
- [ ] User should get a warning at the end regarding these issues with row index and the problematic email.
- [ ] Users should be able to ignore this warning.

**Additional context**
Please see [GER_notes_for Agile_team](https://bcgov.sharepoint.com/:u:/r/teams/00598-TeamZelda/Shared%20Documents/Team%20Zelda/_CTHUB_/Data_2024/GER_SUVI/GER_notes_for_Agile_team.html?csf=1&web=1&e=1xescZ), section 5 for my implementation using a python package called [email_validator](https://pypi.org/project/email-validator/).