Rework steady heartbeat task

[Alexejhero]

Currently the worst task on submerged in my opinion, this task should be reworked.

My idea was to make it like flappy bird, where there is a minimum target value and maximum target value displayed on the line graph, and the player clicks the heartbeat button to jump up (and waits to fall down), and the goal is to stay in the target zone for a certain amount of time, but I guess anything else works as well as long as it makes it better.