fix: always provide empty segments list in feature env strategies (#7880)

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## About the changes

When reading feature env strategies and there's no segments it returns
empty list of segments now. Previously it was undefined leading to
overly verbose change request diffs.

<img width="669" alt="Screenshot 2024-08-14 at 16 06 14"
src="https://github.com/user-attachments/assets/1ac6121b-1d6c-48c6-b4ce-3f26c53c6694">


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src/lib/features/feature-toggle/feature-toggle-strategies-store.ts

@@ -855,6 +855,7 @@ class FeatureStrategiesStore implements IFeatureStrategiesStore {
             constraints: r.constraints || [],
             variants: r.strategy_variants || [],
             parameters: r.parameters,
+            segments: [],
             sortOrder: r.sort_order,
             id: r.strategy_id,
             title: r.strategy_title || '',

src/lib/features/feature-toggle/tests/feature-toggles.e2e.test.ts

@@ -3055,7 +3055,7 @@ test('should create a strategy with segments', async () => {
                 (strat) => strat.id === strategyOne.id,
             );
 
-            expect(strategy.segments).toBe(undefined);
+            expect(strategy.segments).toEqual([]);
         });
 });