Reintroduce previously deprecated transaction/span attributes

[meiao]

Overview

Restores removed http attributes from Transactions and Spans under a configuration option.
By default sends both legacy and standard attributes.

Related Github Issue

Fixes #1662

Checks

• Your contributions are backwards compatible with relevant frameworks and APIs.
• Your code does not contain any breaking changes. Otherwise please describe.
• Your code does not introduce any new dependencies. Otherwise please describe.

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (2cbec36) 70.71% compared to head (52408c3) 70.69%.
Report is 5 commits behind head on main.

Files	Patch %	Lines
...om/newrelic/agent/config/AttributesConfigImpl.java	50.00%	1 Missing and 4 partials ⚠️
...wrelic/agent/dispatchers/WebRequestDispatcher.java	55.55%	0 Missing and 4 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1671      +/-   ##
============================================
- Coverage     70.71%   70.69%   -0.03%     
- Complexity     9953     9958       +5     
============================================
  Files           828      828              
  Lines         39940    39967      +27     
  Branches       6032     6048      +16     
============================================
+ Hits          28243    28254      +11     
- Misses         8978     8984       +6     
- Partials       2719     2729      +10     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.