remove ai-model-preferences var env and config (#20859)

Split the single AI_MODEL_PREFERENCES JSON config into 4 array configs
and migrates existing workspace data.

packages/twenty-server/src/utils/try-parse-json-array.ts

@@ -0,0 +1,9 @@
+export const tryParseJsonArray = (value: string): unknown[] | null => {
+  try {
+    const parsed = JSON.parse(value);
+
+    return Array.isArray(parsed) ? parsed : null;
+  } catch {
+    return null;
+  }
+};