Don't modify edit links if previous request had the classic editor query param

[dkotter]

Description of the Change

Currently, if you click to edit a post in the classic editor and then go back to the edit post list, the next post you click on will automatically open in the classic editor, no matter what edit option you choose.

This PR removes the code that is responsible for this, as it's not ideal to force the classic editor when a user hasn't actually selected that option.

Alternate Designs

None

Benefits

Each post you edit will open the right editing experience, irregardless of any previously selected choice

Possible Drawbacks

None

Verification Process

1. Click to edit a post in the classic editor
2. Go back to the post list view
3. Click the regular edit button on a different post
4. Note that it should open in the block editor

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

Closes #9