Making Admin and Bundler options required instead of optional to avoid confusion

[swordensen]

Description

• [ x] I have read and understand the CONTRIBUTING.md document in this repository.

Type of change

• [x ] Chore (non-breaking change which does not add functionality)
• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Change to the templates directory (does not affect core functionality)
• [ ] Change to the examples directory (does not affect core functionality)
• [ ] This change requires a documentation update

Checklist:

• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] Existing test suite passes locally with my changes
• [ ] I have made corresponding changes to the documentation

[swordensen]

Without setting the bundler I was getting the following error:

TypeError: Cannot read properties of undefined (reading 'dev')

I was migrating from payload v1 to payload v2 and it turns out I was just missing a bundler option. If payload does not use a default bundler then we should probably mark these fields as required.