framework-integ: Support specification of awsPcaAuthorityArn in framework integ tests

[ren-yamanashi]

Describe the issue

Currently, the following document on integ testing of the framework does not describe the specification of awsPcaAuthorityArn.

https://github.com/aws/aws-cdk/blob/main/packages/%40aws-cdk-testing/framework-integ/README.md

However, in the following MR that I am currently working on, I encountered a use case where I want to specify awsPcaAuthorityArn in the integ test.

#32605

Therefore, I would like you to add support for specifying awsPcaAuthorityArn in integ tests.
(I expect it will probably be in the form of adding an environment variable).

Thank you in advance.

Links

https://github.com/aws/aws-cdk/blob/main/packages/%40aws-cdk-testing/framework-integ/README.md

[pahud]

I guess you might need tricks like this?

aws-cdk/packages/@aws-cdk-testing/framework-integ/test/aws-certificatemanager/test/integ.dns-validated-certificate.ts

Lines 22 to 26 in 8718767

	const hostedZoneId = process.env.CDK_INTEG_HOSTED_ZONE_ID ?? process.env.HOSTED_ZONE_ID;
	if (!hostedZoneId) throw new Error('For this test you must provide your own HostedZoneId as an env var "HOSTED_ZONE_ID". See framework-integ/README.md for details.');
	const hostedZoneName = process.env.CDK_INTEG_HOSTED_ZONE_NAME ?? process.env.HOSTED_ZONE_NAME;
	if (!hostedZoneName) throw new Error('For this test you must provide your own HostedZoneName as an env var "HOSTED_ZONE_NAME". See framework-integ/README.md for details.');
	const domainName = process.env.CDK_INTEG_DOMAIN_NAME ?? process.env.DOMAIN_NAME;

[ren-yamanashi]

I guess you might need tricks like this?

aws-cdk/packages/@aws-cdk-testing/framework-integ/test/aws-certificatemanager/test/integ.dns-validated-certificate.ts

Lines 22 to 26 in 8718767

	const hostedZoneId = process.env.CDK_INTEG_HOSTED_ZONE_ID ?? process.env.HOSTED_ZONE_ID;
	if (!hostedZoneId) throw new Error('For this test you must provide your own HostedZoneId as an env var "HOSTED_ZONE_ID". See framework-integ/README.md for details.');
	const hostedZoneName = process.env.CDK_INTEG_HOSTED_ZONE_NAME ?? process.env.HOSTED_ZONE_NAME;
	if (!hostedZoneName) throw new Error('For this test you must provide your own HostedZoneName as an env var "HOSTED_ZONE_NAME". See framework-integ/README.md for details.');
	const domainName = process.env.CDK_INTEG_DOMAIN_NAME ?? process.env.DOMAIN_NAME;

@pahud

Yes, such a statement is required. However, there is no information in the documentation on which environment variable to use when specifying awsPcaAuthorityArn.

Also, this environment variable is needed when performing CI, but I do not know what value to specify for which key.

Therefore, I would like to ask for the following two things

1. definition of the environment variable to use when using awsPcaAuthorityArn(and change docs)
2. adding 1 environment variable to the environment variables used by CI