FE: Update scan result severity level criteria to display automatically

Why are we doing this work

• see Policy Editor Rule Mode UX enhancements (&11079) for details

Implementation plan

• frontend update filter to not use null and [], but instead to get the information from the yaml
• frontend display severity_levels criteria UI by default with All selected selected in security_scan_rule_builder
• frontend when a user selects All, the severity_levels: [] shows in the yaml in security_scan_rule_builder

Verification steps

1. Navigate to scan result policy editor rule mode
2. verify that severity_levels criteria UI shows with All severity levels selected in rule mode and the severity_levels key is not in the yaml
3. User selects specific severity
4. verify that severity_levels key appears in yaml with selected values in an array
5. User selects All severity levels
6. verify that severity_levels key in yaml is removed