ci: update test for KUnit tests according to new output

Commit 6c738b5 ("kunit: improve KTAP compliance of KUnit test
output") changed the format of the `ok` line.

Thus, in our test that checks that KUnit tests succeeded, change it too.

Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

.github/workflows/ci.yaml

@@ -267,7 +267,7 @@ jobs:
 
       # Check
       - run: |
-          grep '] ok 1 - rust_kernel_doctests$' qemu-stdout.log
+          grep '] ok 1 rust_kernel_doctests$' qemu-stdout.log
 
       - run: |
           grep '] rust_minimal: Rust minimal sample (init)$'     qemu-stdout.log