VOTE-2162 remove old theme

[SamiraMSadat]

Jira ticket

https://cm-jira.usa.gov/secure/RapidBoard.jspa?rapidView=4046&projectKey=VOTE&view=planning&selectedIssue=VOTE-2162&quickFilter=23166&issueLimit=100#

Description

Remove the old theme that is not being used for the new site. This change should not impact the site.

Deployment and testing

Post-deploy steps

1. lando retune

QA/Testing instructions

1. Confirm the login page looks as expected
2. Confirm the rest of the site's styling looks as expected and there is no old styling implemented on the site

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.