fix(Netflix): resolve pausing and small images option issues

[iuriineves]

Description

• Set timestamps to 0 when the video is paused - setting it to null breaks the .setActivity() function, only updating the information when the video is running;
• Set smallImageKey to null when showSmallImages is false - setting it to "" didn't remove the image.

Acknowledgements

• I read the Presence Guidelines
• I linted the code by running yarn format
• The PR title follows the repo's commit conventions

Screenshots

Proof showing the creation/modification is working as expected

(pausing)

(showSmallImages set to false)