add metrics counter for finished spawned tasks

[alessandromazza98]

Closes #4479

I add two fields to TaskExecutorMetrics:

• finished_critical_tasks
• finished_regular_tasks

And then updates the spawn and spawn_critical functions in order to properly increase finished critical and regular tasks metrics as well.

[codecov]

Codecov Report

Merging #4481 (a99eaf7) into main (d2647dc) will increase coverage by 0.00%.
Report is 13 commits behind head on main.
The diff coverage is 90.90%.

Files Changed	Coverage Δ
crates/tasks/src/metrics.rs	57.14% <85.71%> (+32.14%)	⬆️
crates/tasks/src/lib.rs	66.79% <93.33%> (+1.30%)	⬆️

... and 26 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	16.67% <0.00%> (+0.05%)	⬆️
unit-tests	63.81% <90.90%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
reth binary	29.71% <ø> (ø)
blockchain tree	83.58% <ø> (ø)
pipeline	90.56% <ø> (ø)
storage (db)	75.06% <ø> (+0.08%)	⬆️
trie	94.88% <ø> (ø)
txpool	47.50% <ø> (+0.07%)	⬆️
networking	77.42% <ø> (-0.03%)	⬇️
rpc	57.44% <ø> (+0.07%)	⬆️
consensus	63.40% <ø> (ø)
revm	31.74% <ø> (ø)
payload builder	6.34% <ø> (ø)
primitives	86.18% <90.90%> (+0.03%)	⬆️

[mattsse]

if you want to get extra fancy you can do something like

struct IncCounterOnDrop(Counter)

impl Drop for IncCounterOnDrop {
  fn drop(&self) {
    // incr
  }
}

this would also solve the issue that on panic the counter wouldn't get decreased atm

so wrap the relevant counter in the helper type and move into the task closure

[mattsse]

this works, thanks