Fix visibility of selection handles in iOS when text is LTR + RTL

[mazunin-v-jb]

Adjusted check of visibility of selection handles in iOS - they won't be shown when they are visible less than 80% of their size. This change is required for making selection handles visible when a single line textfield contains LTR + RTL text, before this fix selection handles weren't visible. In addition, during scrolling the long textfield, selection handles will be hiding more smoothly than before.

Fixes: https://youtrack.jetbrains.com/issue/COMPOSE-1359/iOS-Selection-Handles-work-weirdly-when-text-is-RTL-LTR

Testing

Open the test app, go Android TextField Samples -> Basic input fields, write some LTR text in any textfield with RTL text, then try to select text. Selection Handles should be visible

Release Notes

Fixes - iOS

• visibility of selection handles in single-line textfields with LTR + RTL text in iOS

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