MultiComboBox not usable on IOS device

[fifoosid]

Describe the bug
The MultiComboBox is almost impossible to be used on IOS

To reproduce
Steps to reproduce the behavior:
0. Use any IOS touch device(iphone, ipad...)

1. Go to https://sap.github.io/ui5-webcomponents/master/playground/components/MultiComboBox/
2. Check the second sample(MultiComboBox with items)
3. Click on the input field of the multicombobox.(not the arrow down)
4. You will see how the input on the page(and not the one in the dialog is focused), the page is zoomed and the list items are not visible

Expected behavior
If you click on the arrow down in the roght side of the multicombobox, the correct behaviour can be observed

Screenshots

Context

• UI5 Web Components version: master branch
• OS/Platform: IOS 14.2
• Browser (if relevant): Safari, Chrome

[ilhan007]

Lowering the Priority to High, I agree that the issue is important, but there is no real business impact currently.

[ilhan007]

Hello @SAP/ui5-webcomponents-topic-rl this is for you, take a look of the issue with the MultiCbx on phone.