Go to Definition treats go_proto_library.importpath as Bazel label and runs invalid query

When I trigger Go to Definition on a quoted importpath value in a BUILD file, the extension appears to treat that value as a Bazel label and runs bazel query on it.

Example (sanitized):

```
go_proto_library(
name = "metrics_go_proto",
importpath = "github.com/example-org/example-repo/protos/vision/metrics_go_proto",
protos = [":metrics_proto"],
)
```

Observed query (sanitized):

```
bazel query //vision/stereo:github.com/example-org/example-repo/protos/vision/metrics_go_proto
```

Observed error:

```
Bazel query failed with code 7
ERROR: no such target '//vision/stereo:github.com/example-org/example-repo/protos/vision/metrics_go_proto'
```

Expected behavior:

- `importpath` should not be interpreted as a Bazel label.
- Go to Definition should only query valid labels (for example `//...`, `@repo//...`, `:...`) or skip non-label attributes like `importpath`.

Notes:

The actual target label resolves fine (for example //vision/stereo:metrics_go_proto).
This looks like extension-side label parsing/heuristic behavior, not a rules_go target definition issue.

Start from the Go to Definition handling for quoted attributes in BUILD files and reproduce the issue with the provided go_proto_library example. Trace the generated bazel query and ensure importpath is skipped while valid labels such as //vision/stereo:metrics_go_proto remain queryable; done when the invalid query is no longer run.

Written by the indexing model from the issue text.