Remove changelogs with invalid extensions

All of these were in past releases, so missed their chance to be included in the
main changelog :-(

changelogs/unreleased/12673-fix_v3_project_hooks_build_events

----
-title: "Fix v3 api project_hooks POST and PUT operations for build_events"
-merge_request: 12673
-author: Richard Clamp

changelogs/unreleased/12892-reset-css-text-align-to-initial-for-rtl.md

----
-title: "reset text-align to initial to let elements with dir="auto" align texts to right in RTL languages ( default is left )"
-merge_request: 12892
-author: goshhob

changelogs/unreleased/22619-add-an-email-address-to-unsubscribe-list-header-in-email

----
-title: Handle unsubscribe from email notifications via replying to reply+%{key}+unsubscribe@ address
-merge_request: 6597
-author:

changelogs/unreleased/26908-make-timelogs-use-foreign-keys

----
-title: Refactor Timelogs structure to use foreign keys.
-merge_request: 8769
-author:

changelogs/unreleased/32340-correct-jobs-api-documentation

----
-title: "Correction to documention for manual steps on the Jobs API"
-merge_request: 11411
-author: Zac Sturgess
\ No newline at end of file

changelogs/unreleased/35942-api-binary-encoding.yaml

----
-title: "Fix API to serve binary diffs that are treated as text."
-merge_request: 14038

changelogs/unreleased/add-mock-deployment-and-monitoring-service-for-development.yaml

----
-title: Added mock deployment and monitoring service with environments fixtures
-merge_request:
-author:

changelogs/unreleased/repository-name-emojis

----
-title: Added ability to put emojis into repository name
-merge_request: 7420
-author: Vincent Composieux