fix: remove traceparent from cachekey should not remove traceparent from original object (#64727)
### What?
I submitted PR #64499 , it got merged, but it contains a mistake.
I'm terribly sorry about this!
By removing the traceparent from the cachekey, we mistakenly removed the
header from the original object.
Causing the actual request to be executed without the traceparent
header.
### Why?
Creating a cachekey should not alter the original object.
### How?
Flip the arguments for Object.assign
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Co-authored-by: Jeffrey <jeffrey@jeffreyzutt.nl>
Co-authored-by: JJ Kasper <jj@jjsweb.site>