**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.


airflow/sensors/filesystem.py
#
#
#
#
import datetime
import os
from glob import glob
from airflow.hooks.filesystem import FSHook
from airflow.sensors.base import BaseSensorOperator
class FileSensor(BaseSensorOperator):
    """
    Waits for a file or folder to land in a filesystem.
    If the path given is a directory then this sensor will only return true if
    any files exist inside it (either directly, or within a subdirectory)
    :param fs_conn_id: reference to the File (path)
        connection id
    :type fs_conn_id: str
    :param filepath: File or folder name (relative to
        the base path set within the connection), can be a glob.
    :type filepath: str
    """
    template_fields = ('filepath',)
    ui_color = '#91818a'
    def __init__(self, *, filepath, fs_conn_id='fs_default', **kwargs):