#24369 reverted the
commit that introduced migration 115. Instead of deleting 115, it
modified it. The problem with this is:
- the migration now does nothing
- the migration can't just be updated in the future, because after it
runs once for a user, it will never be run again

What we need to do is delete migration 115 and then rename the
subsequent migrations to one number lower (and update their contents to
reflect these new migration numbers. Then, when the reverted changes are
restored, the migration can be re-added as the new highest numbered
migration.

This PR makes the changes needed to delete migration 115 over multiple
commits, for ease of review. Reviewing this PR is really easy _if_ you
review commit by commit (but Github can't easily display the simplicity
of the changes when they are all together). Below I have briefly
described each commit and included a screenshot of what you will see if
you click the link to look at that commit directly

e7d4cb5 **Deletes** the existing
migration 115 files
![Screenshot from 2024-05-21
05-03-03](https://github.com/MetaMask/metamask-extension/assets/7499938/f062276d-5fa8-4857-880a-4ae1daefb229)

8d78df3 **Renames** the existing
migration 116 files to migration 115 files
![Screenshot from 2024-05-21
05-03-23](https://github.com/MetaMask/metamask-extension/assets/7499938/199e8d94-5101-472a-83b7-13b2d94037b9)

3023d17 **Renames** the existing
migration 117 files to migration 116 files
![Screenshot from 2024-05-21
05-03-39](https://github.com/MetaMask/metamask-extension/assets/7499938/7fddc54d-8e0a-44f7-ad14-00cf12041f14)

23f121b **Renames** the existing
migration 118 files to migration 117 files
![Screenshot from 2024-05-21
05-04-15](https://github.com/MetaMask/metamask-extension/assets/7499938/7c97a3aa-7f22-4db2-a7b7-bacbd9fca7b9)

f6cbb92 **Renames** the existing
migration 119 files to migration 118 files
![Screenshot from 2024-05-21
05-04-28](https://github.com/MetaMask/metamask-extension/assets/7499938/223cc3f9-b3a2-4b42-ae9a-3eba526d8968)

f40afd7 **Modifies** the renamed files
from the previous commits, so that any number within those files in the
range 115-119 is replaced by the number one below.
![Screenshot from 2024-05-21
05-05-29](https://github.com/MetaMask/metamask-extension/assets/7499938/3a680ca8-1c30-4e6e-bace-7c8b206cdb7e)

088ecd5 Just deletes 1 line from
app/scripts/migrations/index.js

[![Open in GitHub
Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/MetaMask/metamask-extension/pull/24666?quickstart=1)

1. Create a local build on the master branch, install and onboard
2. Create a build on this branch, install
3. In the background console, you should see logs that show migrations
115 to 118 running successfully

- [ ] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.