feat: Implement a tick box for organizers/admin to override Email

[shreyanshdwivedi]

Fixes #2953

Short description of what this resolves:

When a speaker registers they have to enter an email. It must be possible to override this requirement for organizers/admins

Changes proposed in this pull request:

• Adds a checkbox to override email while creating speaker from event dashboard

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the Upstream development branch.
• The acceptance, integration, unit tests and linter pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[mrsaicharan1]

As the code is repetitive, is it possible to shift it to a mixin?

[shreyanshdwivedi]

@CosmicCoder96 @uds5501 please review

[shreyanshdwivedi]

@kushthedude @CosmicCoder96 pleaae review