Revert Cleanup interaction of exemplar and aggregation

[XSAM]

Topic: #5249

This reverts commit 8041156 (PR: #5899) due to the performance degradation found by Benchmarks CI https://github.com/open-telemetry/opentelemetry-go/actions/runs/11447364022/job/31848519243

Here is the benchmark test on my machine:

goos: darwin
goarch: arm64
pkg: go.opentelemetry.io/otel/sdk/metric
                                       │   old.txt   │                new.txt                 │
                                       │   sec/op    │    sec/op     vs base                  │
Instrument/instrumentImpl/aggregate-10   3.378µ ± 3%   49.366µ ± 1%  +1361.40% (p=0.000 n=10)
Instrument/observable/observe-10         2.288µ ± 2%   37.791µ ± 1%  +1551.73% (p=0.000 n=10)
geomean                                  2.780µ         43.19µ       +1453.65%

                                       │   old.txt    │                 new.txt                 │
                                       │     B/op     │     B/op       vs base                  │
Instrument/instrumentImpl/aggregate-10   1.245Ki ± 1%   22.363Ki ± 0%  +1696.08% (p=0.000 n=10)
Instrument/observable/observe-10           823.0 ± 1%    17432.5 ± 0%  +2018.17% (p=0.000 n=10)
geomean                                  1.000Ki         19.51Ki       +1850.48%

                                       │  old.txt   │                new.txt                │
                                       │ allocs/op  │  allocs/op   vs base                  │
Instrument/instrumentImpl/aggregate-10   1.000 ± 0%   21.000 ± 0%  +2000.00% (p=0.000 n=10)
Instrument/observable/observe-10         1.000 ± 0%   16.000 ± 0%  +1500.00% (p=0.000 n=10)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.6%. Comparing base (7a153a0) to head (b1d8e66).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #5913   +/-   ##
=====================================
  Coverage   84.6%   84.6%           
=====================================
  Files        271     272    +1     
  Lines      22825   22834    +9     
=====================================
+ Hits       19310   19320   +10     
+ Misses      3171    3170    -1     
  Partials     344     344           

see 6 files with indirect coverage changes

[dashpole]

It is probably from replacing nil with AlwaysOffFilter, if I had to guess.