Dashboards: Fix Mobile support dashboard issues on new iOS 16.3

[axelavargas]

What is this feature?

In some cases, using -webkit-overflow-scrolling: touch can lead to rendering issues, such as elements not being visible. We received reports of variables and some panels not being visible on iOS devices with version 16.3 or higher. Upon investigation, we found that our CustomScrollbar component uses a library that adds this property, causing these issues. In this PR, I override that style to auto to fix the visibility problems.

I tested the solution using BrowserStack (on a real device), and it resolved the issue.

screenRecording-29-2-2023-16-29.mp4

Which issue(s) does this PR fix?:

Fixes #61915

Special notes for your reviewer:

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.
• There are no known compatibility issues with older supported versions of Grafana, or plugins.
• It passes the Hosted Grafana feature readiness review for observability, scalability, performance, and security.

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[juanicabanas]

Like it! 🚀

[polibb]

looks good!

[shezhangzhang]

Can we merge this awesome PR to 9.2.x? Because 9.3.x+ changed a lot (navigation), we stay at 9.2.x