Hide the OpenSeadragon navigator while drawing (#1514)

[blms]

In this PR

Per #1514:

• Prevent the OSD navigator from getting in the way of drawing polygons and rectangles, by hiding it during drawing

[codecov[bot]]

Codecov Report

Merging #1524 (d7d6934) into develop (214fbf9) will increase coverage by 0.03%. Report is 3 commits behind head on develop. The diff coverage is n/a.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1524 +/- ## =========================================== + Coverage 98.43% 98.47% +0.03% =========================================== Files 221 221 Lines 12525 12833 +308 =========================================== + Hits 12329 12637 +308 Misses 196 196 ```