Add to/fromJSON methods to State and Accounts

This is needed since all storage in manifest v3 is key-value-pair-based
and session storage of most data is actually serialized into an
encrypted string.

libs/common/spec/services/stateMigration.service.spec.ts

@@ -116,8 +116,8 @@ describe("State Migration Service", () => {
                 key: "orgThreeEncKey",
               },
             },
-          },
-        },
+          } as any,
+        } as any,
       });
 
       const migratedAccount = await (stateMigrationService as any).migrateAccountFrom4To5(