Remove WP filter unnecessarily applied twice

[johnwatkins0]

Description of the Change

This resolves #69 by removing the second instance of the autoshare_for_twitter_tweet filter, which is only meant to appear once.

Alternate Designs

Benefits

Avoid side effects from having the filter applied twice.

Possible Drawbacks

Verification Process

The filter provides a way to modify tweet text send to the Twitter endpoint. Verification could involve checking that features making use of this filter are unaffected.

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

#69

Changelog Entry

Remove redundant filter

[dinhtungdu]

LGTM 👍