Modifying unit tests for editable_text

[nturgut]

Description

Adding a log.clear statement to a unit test in editable_text_test.dart
Also add min/max lines to the tested widget which will create a better test case for testing cached size.

Tests

This PR modify the unit test and add more cases.

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[mdebbar]

LGTM!

[nturgut]

Thanks for the quick review!