feat(baggage): Added double baggage prevention logic

[harshit078]

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Closes #19158

[Lms24]

Hey @harshit078 thanks for taking over the issue and opening the PR! I see there are some tests failing regarding the mergeBaggageHeaders function. Are you aware of this and looking into fixing it or should we take over? Just let me know :)

There's one test named "overwrites existing Sentry entries with new ones", so I'm wondering why we'd end up with duplicated entries. This might be related to #17355 which got merged yesterday.

[harshit078]

Hey @Lms24 , yes I am resolving the current failing tests and pushing a fix for it. I'll mark the PR as ready to review as soon as all tests pass