[RUMF-642] do not return internal context if the session is untracked

[BenoitZugmeyer]

Motivation

When the session is untracked, we still create a new view object, but we don't send it to the intake. It should not be used by logs or trace because it would lead to an undefined view event.

Changes

Make sure the session have an id and is tracked before exposing the internal context

Testing

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I have gone over the contributing documentation.

[mquentin]

Nice !

[codecov-commenter]

Codecov Report

Merging #498 into master will increase coverage by 0.29%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #498      +/-   ##
==========================================
+ Coverage   87.39%   87.69%   +0.29%     
==========================================
  Files          34       34              
  Lines        2111     2113       +2     
  Branches      416      417       +1     
==========================================
+ Hits         1845     1853       +8     
+ Misses        266      260       -6     

Impacted Files	Coverage Δ
packages/rum/src/rum.ts	90.83% <100.00%> (+4.79%)	⬆️

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