Remove Rails from CI templates and fix LaTeX spelling

What does this MR do?

Fixes: #330699 (closed)

For the pipeline-empty-state experiment, we rendered the list of CI-templates as an experiment to easily start with CI/CD in GitLab.

This MR fixes two issues:

1. There is no CI template for Rails, therefore we remove it in the list of available templates
2. Fixes the spelling of Latex to LaTeX, which also fixes the wrong link to its template

Changelog not required because it's behind a feature flag.

How to test locally

Note: If the following does not work, try to restart the gdk to make sure no feature flag was cached.

• echo 'Feature.enable(:pipeline_empty_state_templates)' | bin/rails c
• Create or go to a project without a .gitlab-ci.yml
• Disabled "Default to Auto DevOps pipeline" in the CI/CD settings of your project (http://localhost:3000/<group_name>/<project_name>/-/settings/ci_cd
• Go to CI/CD -> Pipelines (http://localhost:3000/<group_name>/<project_name>/-/pipelines

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• [-] I have added/updated documentation, or it's not needed. (Is documentation required?)
• [-] I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• [-] I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• [-] I have self-reviewed this MR per code review guidelines.
• [-] This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• • ] I have followed the style guides.

Availability and Testing

• [-] I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• [-] I have tested this MR in all supported browsers, or it's not needed.
• [-] I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.