fix: Incorrect initial global scoping of cross filters

[kgabryje]

SUMMARY

When user first created a new dashboard, initially charts in global scope of cross filters was an empty array (since dashboard was empty). However, after adding new charts, we didn't update the chartsInScope array for global scoping. This PR fixes the bug.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

1. Create a new dashboard
2. Populate with charts (Table chart, Line chart, etc).
3. Click on the Table’s cell to trigger the cross-filtering.
4. Verify that cross filtering from table was applied to other charts

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API