Fix: More accurate heartbeat Interval

[chakflying]

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Description

Fixes #3058

Previously, we await on all the async operations in a beat before scheduling the next beat, which means that any blocking operation and timeout will count towards the interval of the next beat. This will drastically increase the duration for long timeouts, and lead to inconsistent beat intervals.

A very simple fix is to schedule the next beat right at the start, so no other operations can affect the accuracy. This gets the beat interval accuracy down to 5-15ms on a Ryzen 5 5600x, which I think the precise ms will depend on CPU load.

Special handling is added for the push monitor. If you call the Push url faster than your set Interval, this will not solve the issue, but I think it's out of scope for this PR.

Type of change

Please delete any options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I ran ESLint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas
  (including JSDoc for methods)
• My changes generate no new warnings
• My code needed automated testing. I have added them (this is optional task)

Screenshots (if any)

[chakflying]

After discussion in #3490, I came up with an even simpler solution:

When setting the next setTimeout, subtract the time taken to run the current heartbeat. Using this method, the loop will run as fast as possible, but there will not be overlap even if the time to run the heartbeat exceeds the defined interval.

Accuracy remains high at around 2-10ms.

[Saibamen]

Please merge this into 1.23.X branch