fix(list/chart views): Chart Properties modal now has transitions

[rusackas]

SUMMARY

Fixes: https://github.com/apache/superset/issues/11520

The properties modal was previously conditionally rendered, rather than using the visibility prop. This fixes it, and adds a bunch of safe navigation operators to handle the default (null) slice scenario.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

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