KTextTruncator: Make custom styling easier/safer

[nucleogenesis]

Desired behavior

During development on Kolibri, I ran into an issue where text passed to KTextTruncator (which was a long URL) resulted in a strange changes to the total width of the KTextTruncator's output.

The fix here was to set the break-word CSS property to anywhere for this particular case.

The /deep/ styles can be brittle if KTextTruncator changes, so it'd be ideal if KTextTruncator had a prop providing a way to pass custom styles.

Outcomes

• There is a way to avoid using /deep/ styles to affect KTextTruncator
• An issue is created in the Kolibri repo to leverage the changes made to close this PR in the aforelinked commit.