Source Zendesk Support: update descriptions in spec

[ChristoGrab]

What

Small update to the Zendesk Support spec file

How

Added recommended authentication methods for Cloud/OSS to auth description
Added some links to guides for OSS OAuth credentials
Couple of minor clarity/grammar edits

[github-actions]

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[octavia-squidington-iii]

source-zendesk-support test report (commit 0f6faaeb5c) - ✅

⏲️ Total pipeline duration: 12mn18s

Step	Result
Validate airbyte-integrations/connectors/source-zendesk-support/metadata.yaml	✅
Connector version semver check	✅
Connector version increment check	✅
QA checks	✅
Code format checks	✅
Connector package install	✅
Build source-zendesk-support docker image for platform linux/x86_64	✅
Unit tests	✅
Acceptance tests	✅

🔗 View the logs here

☁️ View runs for commit in Dagger Cloud

Please note that tests are only run on PR ready for review. Please set your PR to draft mode to not flood the CI engine and upstream service on following commits.
You can run the same pipeline locally on this branch with the airbyte-ci tool with the following command

airbyte-ci connectors --name=source-zendesk-support test

[octavia-squidington-iii]

source-zendesk-support test report (commit aebb79976a) - ✅

⏲️ Total pipeline duration: 12mn03s

Step	Result
Validate airbyte-integrations/connectors/source-zendesk-support/metadata.yaml	✅
Connector version semver check	✅
Connector version increment check	✅
QA checks	✅
Code format checks	✅
Connector package install	✅
Build source-zendesk-support docker image for platform linux/x86_64	✅
Unit tests	✅
Acceptance tests	✅

🔗 View the logs here

☁️ View runs for commit in Dagger Cloud

Please note that tests are only run on PR ready for review. Please set your PR to draft mode to not flood the CI engine and upstream service on following commits.
You can run the same pipeline locally on this branch with the airbyte-ci tool with the following command

airbyte-ci connectors --name=source-zendesk-support test