fix: specification compliant resource collision precedence

[srikanthccv]

Resource Merge Spec

The resulting resource MUST have all attributes that are on any of the two input resources. If a key exists on both the old and updating resource, the value of the updating resource MUST be picked (even if the updated value is empty).

This commit updates the resource collision precedence.

[codecov]

Codecov Report

Merging #1975 (356e5e2) into main (3588601) will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1975      +/-   ##
==========================================
+ Coverage   92.87%   92.92%   +0.05%     
==========================================
  Files         152      152              
  Lines        5922     5922              
  Branches     1245     1245              
==========================================
+ Hits         5500     5503       +3     
+ Misses        422      419       -3     

Impacted Files	Coverage Δ
packages/opentelemetry-resources/src/Resource.ts	100.00% <ø> (ø)
...ges/opentelemetry-instrumentation-http/src/http.ts	95.51% <0.00%> (+0.81%)	⬆️
...emetry-core/src/platform/node/RandomIdGenerator.ts	93.75% <0.00%> (+6.25%)	⬆️

[dyladan]

Can you add this to the upgrade guidelines in the README since it is a breaking change?

[srikanthccv]

@dyladan I have added the new entry.

[dyladan]

Looks good but I want to wait for @obecny since this PR is only 1 day old and it was a weekend

[obecny]

lgtm,
one comment, hope you can address it before merge.