Regression: No line wrapping in slice title

[rumbin]

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• I have checked the superset logs for python stacktraces and included it here as text if any
• I have reproduced the issue with at least the latest released version of superset
• I have checked the issue tracker for the same issue and I haven't found one similar

Superset version

0.20.3

Expected results

Long slice titles are wrapped to make them fit into the slice.

This it the way it used to be in 0.15.4:

Actual results

The slice title is not wrapped and — depending on the Visialization Type — either overlap the slice boundaries or are hidden within a horizontal scroll range.

Steps to reproduce

Create a slice with a long title and try to fit it into a narrow area on a dashboard.

[rumbin]

Please also notice, that the legend in the Distribution Bar Chart is also entirely gone, unless the slice is given at least one more step in width than the minimal one.

[mistercrunch]

@graceguo-supercat I think this is a regression caused by #3467