Revert "Updated Postgres Spec for where to find engine version, removed calling calling -ev in edit commands (#14735)" (#14794)

This reverts commit 318559dcd7.

extensions/arc/src/models/postgresModel.ts

@@ -53,7 +53,10 @@ export class PostgresModel extends ResourceModel {
 
 	/** Returns the major version of Postgres */
 	public get engineVersion(): string | undefined {
-		return this._config?.spec.engine.version;
+		const kind = this._config?.kind;
+		return kind
+			? kind.substring(kind.lastIndexOf('-') + 1)
+			: undefined;
 	}
 
 	/** Returns the IP address and port of Postgres */