Magnifier not working as expected [BUG]

[cjchirag7]

Describe the bug
There are 2 bugs -

1. Magnifier gets highlighted in the toolbar menu but it doesn't work when Ctrl + M is pressed.
2. Also, when magnifier is selected, and after that 'measurement' or 'present labels' or any other tool is selected, it also gets simultaneously selected (highlighted), but doesn't work.

To Reproduce
Steps to reproduce the behavior for bug 2 :

1. Go to the viewer page by opening any slide
2. Hover over magnifier icon
3. Click on '1.0' option
4. Click on any other tool like measurement, present labels, etc.

Expected behavior
When the other tool is selected, magnifier should be deselected automatically.

Screencast
When magnifier is selected, following measurement, the measurement tool gets highlighted but doesn't work:

Desktop (please complete the following information):

• OS: Ubuntu 18.04 LTS
• Browser Chrome
• Version 80.0.3987.132 (Official Build) (64-bit)

Additional context
This is due to improper event 'click', used for the dropdown tools. The event 'change' should be used instead, to prevent this problem.

[cjchirag7]

PR #297 fixed this.