[Enhancement] Improve visibility of progress bar on video content

Description

It's been reported (Slack conversation link) that the progress bar on videos on Learn are visually difficult to locate. This is especially so when the video content is showing the wp-admin screen... which many of our videos do. (See screenshot below.) A better interface would improve accessibility.

Step-by-step reproduction instructions

1. Go to learn.wordpress.org
2. Click on Tutorials
3. Choose any tutorial and play video
4. Progress bar is difficult to locate, and will only appear large once one has hovered over the video

Suggested improvement

• Change color scheme (bold colors?) so it doesn't conflict with the default wp-admin screen often shown in videos.

But this is still very much open to other ideas and suggestions.

I realize this could involve enhancements to the video player we're using. I wanted to log the idea here so it doesn't get lost.

Screenshots or screen recording (optional)

Environment information

• Reproduced on Chrome on MacOS

Start by reproducing the issue at learn.wordpress.org through Tutorials, using the reported Chrome on macOS environment, and inspect how the video player displays its progress bar over wp-admin footage. Done means the progress bar is consistently easy to locate and the change improves accessibility without being limited to the suggested color scheme.