Allow non-comparable global types

[MrAlias]

The global MeterProvider, TracerProvider, and TextMapPropagator should not panic when they are set to a non-comparable implementation of each.

Fix #2772

[codecov]

Codecov Report

Merging #2773 (3272707) into main (376c23c) will decrease coverage by 0.0%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main   #2773     +/-   ##
=======================================
- Coverage   76.8%   76.8%   -0.1%     
=======================================
  Files        181     181             
  Lines      12188   12193      +5     
=======================================
+ Hits        9362    9365      +3     
- Misses      2601    2603      +2     
  Partials     225     225             

Impacted Files	Coverage Δ
internal/global/state.go	100.0% <100.0%> (ø)
metric/internal/global/state.go	100.0% <100.0%> (ø)
exporters/jaeger/jaeger.go	90.3% <0.0%> (-0.9%)	⬇️

[dmathieu]

This is fine by me. Just want to reference that the comparison was moved out of the Once following this comment.

[MrAlias]

This is fine by me. Just want to reference that the comparison was moved out of the Once following this comment.

That still seems like the appropriate behavior for the reasons listed in the linked comment, we don't want to fail the delegation forever if the user sets the delegate to itself. It was correct for that change to have been made. Iterative improvement is the name of the game.

[MrAlias]

Merging prior to the 1 working day project policy. The goal is to get a patch release out ASAP with this change.