Fix mobile modal overflow

[gillesdemey]

The modal was overflowing on mobile viewports following changes in https://github.com/jesec/flood/pull/597

Description

This PR unsets the min-width for mobile viewports.

Related Issue

Fixes https://github.com/jesec/flood/issues/711

Screenshots

Types of changes

• [ ] Breaking change (changes that break backward compatibility of public API or CLI - semver MAJOR)
• [ ] New feature (non-breaking change which adds functionality - semver MINOR)
• [x] Bug fix (non-breaking change which fixes an issue - semver PATCH)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (5acf61b) 73.13% compared to head (06500ed) 73.13%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #713 +/- ## ======================================= Coverage 73.13% 73.13% ======================================= Files 62 62 Lines 11375 11375 Branches 959 963 +4 ======================================= Hits 8319 8319 Misses 3042 3042 Partials 14 14 ```

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[trim21]

thanks