Update Sisense Community links

What does this MR do?

Affected sections;

• https://about.gitlab.com/handbook/business-technology/data-team/platform/periscope/#self-service-dashboard-development-1
• https://about.gitlab.com/handbook/business-technology/data-team/platform/periscope/#sisense-resources

The Sisense Community links are broken (https://support.sisense.com/kb/en/hc/en-us/community/topics/360001558233-Sisense-for-Cloud-Data-Teams).

They were added in !54533 (merged) and !63508 (merged). This MR changes those links to the new community page: https://community.sisense.com.

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Screenshots

https://support.sisense.com/kb/en/hc/en-us/community/topics/360001558233-Sisense-for-Cloud-Data-Teams

https://community-old.sisense.com/hc/en-us/community/topics/360001558233-Sisense-for-Cloud-Data-Teams

https://community.sisense.com