Bump vue-template-compiler and graphql-tools in /frontend

Removes [vue-template-compiler](https://github.com/vuejs/vue). It's no longer used after updating ancestor dependency [graphql-tools](https://github.com/ardatan/graphql-tools/tree/HEAD/packages/graphql-tools). These dependencies need to be updated together.


Removes `vue-template-compiler`

Updates `graphql-tools` from 6.2.3 to 6.2.6
- [Release notes](https://github.com/ardatan/graphql-tools/releases)
- [Changelog](https://github.com/ardatan/graphql-tools/blob/master/packages/graphql-tools/CHANGELOG.md)
- [Commits](https://github.com/ardatan/graphql-tools/commits/[email protected]/packages/graphql-tools)

---
updated-dependencies:
- dependency-name: vue-template-compiler
  dependency-type: indirect
- dependency-name: graphql-tools
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>