feat(language): add Gleam coding language (@binajmen) (monkeytypegame#6771)

### Description

Adding the Gleam language!

https://gleam.run/

### Checks

- [x] Adding a language?
- Make sure to follow the [languages
documentation](https://github.com/monkeytypegame/monkeytype/blob/master/docs/LANGUAGES.md)
  - [x] Add language to `packages/contracts/src/schemas/languages.ts`
- [x] Add language to exactly one group in
`frontend/src/ts/constants/languages.ts`
  - [x] Add language json file to `frontend/static/languages` 
- [x] Check if any open issues are related to this PR; if so, be sure to
tag them below.
- [x] Make sure the PR title follows the Conventional Commits standard.
(https://www.conventionalcommits.org for more info)
- [x] Make sure to include your GitHub username prefixed with @ inside
parentheses at the end of the PR title.

Author: binajmen

frontend/src/ts/constants/languages.ts

@@ -340,6 +340,7 @@ export const LanguageGroups: Record<string, Language[]> = {
     "code_arduino",
     "code_systemverilog",
     "code_elixir",
+    "code_gleam",
     "code_zig",
     "code_gdscript",
     "code_gdscript_2",