fix(#1800): increase modal z-index to appear above prettify icon

[devon-wolf]

Description

Related to issue #1800

This PR lifts up the z-index of elements of the .bruno-modal class in order for modals to appear above the "prettify" wand when the GraphQL editor is open.

I confirmed that the wand appeared above any modal I opened, not just the environment config modal mentioned in the issue. The other option that worked was dropping the wand's z-index to 1, but since it was being set with tailwind it was less clean to make that adjustment. Logically, increasing the modal's z-index made sense to me, but I'm happy to change if you prefer!

I did not observe any unusual/unwanted/breaking behavior after this change. Tests all pass.

Before the change:

After the change:

Contribution Checklist:

• [x] The pull request only addresses one issue or adds one feature.
• [x] The pull request does not introduce any breaking changes
• [x] I have added screenshots or gifs to help explain the change if applicable.
• [x] I have read the contribution guidelines.
• [x] Create an issue and link to the pull request.

Note: Keeping the PR small and focused helps make it easier to review and merge. If you have multiple changes you want to make, please consider submitting them as separate pull requests.

Publishing to New Package Managers

Please see here for more information.