Added support for max session time

[merav-aharoni]

Summary

Fixed session max time parameter that was not passed to the server properly.

Details and comments

See Qiskit/qiskit-ibm-runtime#1198.

[coveralls]

Pull Request Test Coverage Report for Build 6969407258

• 2 of 4 (50.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.008%) to 51.705%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_ibm_provider/api/rest/runtime.py	0	1	0.0%
qiskit_ibm_provider/ibm_backend.py	1	2	50.0%

Totals
Change from base Build 6895819583:	-0.008%
Covered Lines:	3411
Relevant Lines:	6597

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💛 - Coveralls