VOTE-2587 Config, templates and po file changes related to string migration

[rayestrada]

Jira ticket

https://cm-jira.usa.gov/browse/VOTE-2587

Description

This PR has 3 objectives:

1. Replace current hardcoded strings in templates with the dynamic variables
2. Add a new 'Submit button label' field for hardcoded string for search component.
3. Remove translations from the po files.

Deployment and testing

Post-deploy steps

1. Pull the latest db from prod to local
2. lando retune

QA/Testing instructions

1. visit http://vote-gov.lndo.site/media/add/image and make sure the caption field only accepts simple formatting options
2. visit https://vote-gov.lndo.site/admin/content/block/2 and add a Submit Button Label
3. Test the display of each of these components for migrated content

• Email sign up block
• government banner block
• search component block
• contact identifier block
• partnership block
• registration tool paragraph

Checklist for the Developer

• A link to the JIRA ticket has been included above.
• No merge conflicts exist with the target branch.
• Automated tests have passed on this PR.
• A reviewer has been designated.
• Deployment and testing steps have been documented above, if applicable.

Checklist for the Peer Reviewers

• The file changes are relevant to the task objective.
• Code is readable and includes appropriate commenting.
• Code standards and best practices are followed.
• QA/Test steps were successfully completed, if applicable.
• Applicable logs are free of errors.

[rayestrada]

I've added new size styles for the imgs. I've also removed the alt text for the U.S.Flag icon and made that decorative following recent updates to the USWDS banner https://designsystem.digital.gov/components/banner/.