test(dbt-tools): remove duplicate "Could not parse" test

The new test at dbt-cli.test.ts L199 ("preserves generic 'Could not
parse' when dbt exited 0 but output unparseable") used the same mock
implementation and asserted the same rejection string as the existing
"Tier 3: throws with helpful message when all tiers fail" test at
L145. The generic-error path is fully covered by Tier 3; any future
change to that behaviour would have had to be kept in sync across
two identical tests.

Addresses cubic-dev-ai review feedback on #933 (P3).

Tests: 23 pass / 0 fail in packages/dbt-tools/test/dbt-cli.test.ts.

Refs #932

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Haider

packages/dbt-tools/test/dbt-cli.test.ts

@@ -196,15 +196,6 @@ describe("execDbtShow", () => {
     await expect(execDbtShow("SELECT 1")).rejects.not.toThrow(/Could not parse dbt show output/)
   })
 
-  test("preserves generic 'Could not parse' when dbt exited 0 but output unparseable", async () => {
-    // Existing behavior — dbt didn't crash, we just couldn't decode its output.
-    mockExecFile.mockImplementation((_cmd: string, _args: string[], _opts: any, cb: Function) => {
-      cb(null, "some unparseable output", "")
-    })
-
-    await expect(execDbtShow("SELECT 1")).rejects.toThrow("Could not parse dbt show output in any format")
-  })
-
   test("falls back to error message when stderr is empty", async () => {
     mockExecFile.mockImplementation((_cmd: string, _args: string[], _opts: any, cb: Function) => {
       const err: any = new Error("spawn ENOENT")