ARROW-15546: [FlightRPC][C++] Remove quotes from cookie header

[jduo]

The client cookie middleware should not wrap values in quotes when
emitting the Cookie header.

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on JIRA? https://issues.apache.org/jira/browse/ARROW

Opening JIRAs ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename pull request title in the following format?

ARROW-${JIRA_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - How to contribute patches

[github-actions]

https://issues.apache.org/jira/browse/ARROW-15546

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[lidavidm]

Thanks. Indeed, it appears quotes are acceptable in Set-Cookie but are not described for Cookie.

[ursabot]

Benchmark runs are scheduled for baseline = 76decf6 and contender = d885d82. d885d82 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Finished ⬇️0.36% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.35% ⬆️0.43%] ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python. Runs only benchmarks with cloud = True
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java