[SDK] Enforce Span Status transition rules

[denizariyan]

Fixes #4546

Changes

• Enforces the span status transition rules as per the spec.
• I choose to enforce it on the span level as that is the common access path with the sdk and as far as my reading, what the spec actually wants us to do. The recordable level is mostly left as-is except where changes are required.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[denizariyan]

I added this because the prev impl actually had this issue with nullptr or non-null terminated strs, not exactly related to this PR but fixed along the way since it's a single line I am changing around anyways

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.45%. Comparing base (e81d957) to head (c1e8793).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4547      +/-   ##
==========================================
+ Coverage   86.41%   86.45%   +0.05%     
==========================================
  Files         524      525       +1     
  Lines       20435    20450      +15     
==========================================
+ Hits        17657    17679      +22     
+ Misses       2778     2771       -7     

Files with missing lines	Coverage Δ
exporters/otlp/src/otlp_recordable.cc	91.34% <100.00%> (+0.07%)	⬆️
exporters/zipkin/src/recordable.cc	88.29% <100.00%> (+0.10%)	⬆️
sdk/include/opentelemetry/sdk/trace/span_status.h	100.00% <100.00%> (ø)
sdk/src/trace/span.cc	94.92% <100.00%> (+1.06%)	⬆️
sdk/src/trace/span.h	100.00% <ø> (ø)

... and 2 files with indirect coverage changes

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[lalitb]

LGTM. With nit comment for header reorg, and changelog. thanks.