**Apache Airflow version**: 2.1.0


**Environment**:

- **Cloud provider or hardware configuration**:
- **OS** (e.g. from /etc/os-release):
- **Kernel** (e.g. `uname -a`):
- **Install tools**:
- **Others**:

**What happened**:  FileSensor does not recognize directories with wildcard glob matching.

**What you expected to happen**: FileSensor would sense a directory that contains files if it matches with the wild card option.

**How to reproduce it**: Create a directory with a pattern that matches a wild card using glob



**Anything else we need to know**: Code from FileSensor source that I believe to cause the issue:

```
for path in glob(full_path):
            if os.path.isfile(path):
                mod_time = os.path.getmtime(path)
                mod_time = datetime.datetime.fromtimestamp(mod_time).strftime('%Y%m%d%H%M%S')
                self.log.info('Found File %s last modified: %s', str(path), str(mod_time))
                return True

            for _, _, files in os.walk(full_path):
                if len(files) > 0:
                    return True
        return False

```
I believe to resolve the issue `full_path` in os.walk should be `path` instead.


tests/sensors/test_filesystem.py
with tempfile.NamedTemporaryFile() as tmp:
            task = FileSensor(
                task_id="test",
                filepath=tmp.name[1:],
                dag=self.dag,
                timeout=0,
            )
            task._hook = self.hook
            task.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE, ignore_ti_state=True)
    def test_wildcard_file(self):
        suffix = '.txt'
        with tempfile.NamedTemporaryFile(suffix=suffix) as tmp:
            fileglob = os.path.join(os.path.dirname(tmp.name), '*' + suffix)
            task = FileSensor(
                task_id='test',
                filepath=fileglob,
                fs_conn_id='fs_default',
                dag=self.dag,
                timeout=0,
            )
            task._hook = self.hook
            task.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE, ignore_ti_state=True)
    def test_subdirectory_not_empty(self):