#9792: fix z index order of catalog in app context wizard

[mahmoudadel54]

Description

Fix z-index order of catalog in app context wizard when user opens it.

• z-index was added before in navbar.less for details panel within dashboard which affected later on showing catalog in context properly.
• So moving it to dashboard.less fixed this issue

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https://github.com/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

#9792

What is the current behavior?
#9792

What is the new behavior?
If user open app context and at the 2nd step "map viewer" opens catalog within burger menu, it opens normally as usual.

Breaking change

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

[MV88]

@ElenaGallo please test it in DEV