Fix json trace/metrics unmarshaling for numbers

[bogdandrutu]

Updates #5312

Also this improves benchmarks since ReadAny was doing an allocation, see:

Before:

/private/var/folders/5c/5p_3jmvd6qx0rsvmb9j7c_s00000gn/T/GoLand/___BenchmarkJSONUnmarshal_in_go_opentelemetry_io_collector_pdata_ptrace.test -test.v -test.paniconexit0 -test.bench ^\QBenchmarkJSONUnmarshal\E$ -test.run ^$
goos: darwin
goarch: amd64
pkg: go.opentelemetry.io/collector/pdata/ptrace
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkJSONUnmarshal
BenchmarkJSONUnmarshal-16    	  334974	      3942 ns/op	    4669 B/op	     231 allocs/op
PASS

After:

/private/var/folders/5c/5p_3jmvd6qx0rsvmb9j7c_s00000gn/T/GoLand/___BenchmarkJSONUnmarshal_in_go_opentelemetry_io_collector_pdata_ptrace.test -test.v -test.paniconexit0 -test.bench ^\QBenchmarkJSONUnmarshal\E$ -test.run ^$
goos: darwin
goarch: amd64
pkg: go.opentelemetry.io/collector/pdata/ptrace
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkJSONUnmarshal
BenchmarkJSONUnmarshal-16    	  374025	      3642 ns/op	    4412 B/op	     219 allocs/op
PASS

Signed-off-by: Bogdan <[email protected]>

[codecov]

Codecov Report

Merging #5924 (61b0c60) into main (d8407ff) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #5924      +/-   ##
==========================================
+ Coverage   91.80%   91.84%   +0.03%     
==========================================
  Files         198      198              
  Lines       12377    12429      +52     
==========================================
+ Hits        11363    11415      +52     
  Misses        800      800              
  Partials      214      214              

Impacted Files	Coverage Δ
pdata/internal/json/number.go	100.00% <100.00%> (ø)
pdata/pmetric/json.go	97.94% <100.00%> (ø)
pdata/ptrace/json.go	100.00% <100.00%> (ø)

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[tigrannajaryan]

Github shows lots of line changes but it seems many of the changes are just moving the code without changing functionality. Can you summarize the changes (other than performance improvement)?

[bogdandrutu]

@tigrannajaryan good point, split the first simple PR #5926 then will split one more time to have focus changes.

A set of the changes are in the CHANGELOG, one thing I don't like about having a CHANGELOG is that you will ask me to copy same thing in the contrib description :)))