Update extensions.json with 7th sea raise tool extension

[Pandasecret1]

Make sure that your submission has the following:

• A link to the raw github markdown file with a YAML front matter definition containing: (this is my first time committing, is this the store.md file link?)
  • The title of your extension
  • A description of your extension
  • The author
  • A hero image
  • An icon
  • Tags (these will help with your extension's discoverability)
  • A link to your extensions manifest

Please, go through these steps before you submit a PR.

• You have done your changes in a separate branch.

• You have a descriptive commit message with a short title (first line).

• You have only one commit (if not, squash them into one commit).

• Your pull request MUST target the main branch on this repository.

• Your pull request puts your extensions details as the last entry in the extensions.json file

[Several-Record7234]

Hi @Pandasecret1,

I've just run 1st-stage verification on your extension and it has failed on quite a few items:

Issues found in manifest type validation.
"title" is required
"description" is required
"author" is required
"image" is required
"icon" is required
"manifest" is required
"learn-more" is required

You can see our guidance and requirements for these aspects here: https://docs.owlbear.rodeo/extensions/tutorial-sharing-your-extension/showcase-your-extension/#create-a-markdown-file-for-your-project

Also, are you not going to host this extension publicly, but only provide it for local use?