refactor: removing pagerduty sync to limitation in Backstage

[t1agob]

Description

This PR removes the logic of syncing from PagerDuty to Backstage. Due to a limitation on how entity relations are emitted in CatalogProcessor the relations existing on file cannot be removed from the entity. This adds some limits on the capacity to fully overwrite relations for an entity and therefore making impossible a full-sync from PagerDuty to Backstage to work.

Once/If the design limitation changes, this capability will be introduced once again.

Issue number: N/A

Type of change

• New feature (non-breaking change which adds functionality)
• Fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• Changes generate no new warnings
• PR title follows conventional commit semantics

If this is a breaking change 👇

• I have documented the migration process
• I have implemented necessary warnings (if it can live side by side)

Acknowledgement

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