Custom header not being sent

[kt474]

Summary

Fixes a bug added in 36d7c15 that caused custom headers to not be sent in the /jobs api request

Details and comments

Fixes #1508

[coveralls]

Pull Request Test Coverage Report for Build 8620119519

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This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 3 of 6 (50.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall first build on custom-header-bug at 83.595%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_ibm_runtime/api/session.py	3	6	50.0%

Totals
Change from base Build 8620102476:	83.6%
Covered Lines:	6227
Relevant Lines:	7449

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💛 - Coveralls

[akihikokuroda]

@kt474 This fixes the issue. Thanks!
Here is the header and middleware_job_id/0187e965-633a-47f7-a696-efb97edf5053 is what we expected.

X-Qx-Client-Application: qiskit-version-2/qiskit_ibm_runtime-0.22.0,qiskit-1.0.2*/qiskit_ibm_runtime~estimator.py/middleware_job_id/0187e965-633a-47f7-a696-efb97edf5053