Add client side validation for analytics options
Add client side validation for analytics options

Pixel tracking is not possible for plaintext emails but the option
can be enabled during plaintext campaign creation (it is validated
server side though).

-> Conditionally disable the pixel tracking option based on the
selected campaign type (plaintext or html).

zhakkarn/Mail-for-Good,karuppiah7890/Mail-for-Good,zhakkarn/Mail-for-Good,karuppiah7890/Mail-for-Good,zhakkarn/Mail-for-Good,karuppiah7890/Mail-for-Good