Support remove on synchronous instruments

[atoulme]

This is a POC implementation to support open-telemetry/opentelemetry-specification#2232

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.1%. Comparing base (c9b7ecf) to head (4d63611).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
sdk/metric/instrument.go	77.1%	6 Missing and 2 partials ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #7541   +/-   ##
=====================================
  Coverage   86.1%   86.1%           
=====================================
  Files        296     296           
  Lines      21594   21670   +76     
=====================================
+ Hits       18598   18665   +67     
- Misses      2623    2630    +7     
- Partials     373     375    +2     

Files with missing lines	Coverage Δ
internal/global/instruments.go	69.2% <100.0%> (+5.5%)	⬆️
metric/noop/noop.go	100.0% <100.0%> (ø)
metric/syncfloat64.go	100.0% <ø> (ø)
metric/syncint64.go	100.0% <ø> (ø)
sdk/metric/internal/aggregate/aggregate.go	100.0% <100.0%> (ø)
...metric/internal/aggregate/exponential_histogram.go	97.3% <100.0%> (+<0.1%)	⬆️
sdk/metric/internal/aggregate/histogram.go	100.0% <100.0%> (ø)
sdk/metric/internal/aggregate/lastvalue.go	100.0% <100.0%> (ø)
sdk/metric/internal/aggregate/sum.go	100.0% <100.0%> (ø)
sdk/metric/meter.go	92.1% <100.0%> (ø)
... and 1 more

... and 1 file with indirect coverage changes

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