The "Play Now" button from a live video wrongly generates two "play" pings

[Softvision-CristinaBadescu]

[Affected versions]:

• Firefox 59.0.2 unbranded
• Firefox Developer Edition 60.0b14
• Min-Vid Shield Study Onboarding 0.4.7 - Shield Study

[Affected Platforms]:

• All Windows

[Prerequisites]:

• Latest Min-Vid v.0.4.7 Shield Study Onboarding ("active" or "activeAndOnboarding" variant) was previously installed on a clean profile.
• The Min Vid player is closed.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites.
2. Navigate to YouTube and search for a live video.
3. Click the "Play Now" button from a live video.
4. Go to "about"telemetry" and observe the type and number of the pings generated by the "Play now" button.

[Expected result]:

• one "player_view" event and "play" method ping is displayed.
• one "overlay_icon"" event and "launch" method ping is displayed.

[Actual result]:

• two "player_view" event and "play" method pings are displayed.

[Notes]:

• Here is a screen recording of the issue: