Assigning an ID attribute to the submit button - signup module D10

Hi dj1999,

In MailchimpSignupPageForm::buildForm()

      '#attributes' => [
        'id' => 'mailchimp-signup-submit-' . $this->getFormId(),
      ],

for the submit ID might be a simpler solution. Can you check if this serves your purposes?

@xenophyle I think this is same if we don't do anything because $this->getFormId() is not different string for all same form.

Ok, makes sense.

Some things to test
- Does this work on a signup form implemented as a page rather than a block?
- Does it work with signup forms that submit with AJAX?
- I'm guessing you tested this but I'm not familiar with the UUID Interface -- are the UUIDs the same for each instance, e.g., if you place a block in the footer on multiple pages will the UUID stay the same across pages, and across installations, for example both on a dev and live site?

There are some changes that look like they may not be central to this fix, like removing the constructor for the subscribe block and using setMessenger. If they are not required for this ticket they should be put in a separate issue to keep this fix easier to understand.

Thanks!