ls [-r] https://gui.dandiarchive.org/#/dandiset/{dandiset_id}/ no longer works
I believe it was working before.  May be related to migration etc
```
(git)lena:~/proj/dandi/dandi-cli-master[master]git
$> dandi ls -r 'https://gui.dandiarchive.org/#/dandiset/000027/'
[]
2021-05-07 10:27:20,427 [    INFO] Logs saved in /home/yoh/.cache/dandi-cli/log/20210507142719Z-3337152.log
Error: https://gui.dandiarchive.org/#/dandiset/000027/ did not redirect to another location which dandi client would know how to handle.
(dev3) 1 79155 ->1 [2].....................................:Fri 07 May 2021 10:27:20 AM EDT:.
(git)lena:~/proj/dandi/dandi-cli-master[master]git
$> dandi ls  'https://gui.dandiarchive.org/#/dandiset/000027/' 
[]
2021-05-07 10:28:25,843 [    INFO] Logs saved in /home/yoh/.cache/dandi-cli/log/20210507142825Z-3337408.log
Error: https://gui.dandiarchive.org/#/dandiset/000027/ did not redirect to another location which dandi client would know how to handle.
(dev3) 1 79156 ->1 [2].....................................:Fri 07 May 2021 10:28:25 AM EDT:.
(git)lena:~/proj/dandi/dandi-cli-master[master]git
$> cat /home/yoh/.cache/dandi-cli/log/20210507142825Z-3337408.log
2021-05-07T10:28:25-0400 [INFO    ] dandi 3337408:140591467472704 dandi v0.16.0+2.g0dabaf4, hdmf v2.3.0, pynwb v1.4.0, h5py v2.10.0
2021-05-07T10:28:25-0400 [INFO    ] dandi 3337408:140591467472704 sys.argv = ['/home/yoh/proj/dandi/dandi-cli-master/venvs/dev3/bin/dandi', 'ls', 'https://gui.dandiarchive.org/#/dandiset/000027/']
2021-05-07T10:28:25-0400 [INFO    ] dandi 3337408:140591467472704 os.getcwd() = /home/yoh/proj/dandi/dandi-cli-master
2021-05-07T10:28:25-0400 [INFO    ] dandi 3337408:140591467472704 Logs saved in /home/yoh/.cache/dandi-cli/log/20210507142825Z-3337408.log
```
diff --git a/dandi/dandiarchive.py b/dandi/dandiarchive.py
index d683720..a847358 100644
--- a/dandi/dandiarchive.py
+++ b/dandi/dandiarchive.py
@@ -322,7 +322,7 @@ class _dandi_url_parser:
             re.compile(
                 rf"{server_grp}#/(?P<asset_type>dandiset)/{dandiset_id_grp}"
                 r"(/(?P<version>[.0-9]{5,}|draft))?"
-                r"(/files(\\?location=(?P<location>.*)?)?)?"
+                r"(/(files(\\?location=(?P<location>.*)?)?)?)?"
             ),
             {},
             "https://<server>[/api]/#/dandiset/<dandiset id>[/<version>]"
diff --git a/dandi/tests/test_dandiarchive.py b/dandi/tests/test_dandiarchive.py
index 859f11c..d675368 100644
--- a/dandi/tests/test_dandiarchive.py
+++ b/dandi/tests/test_dandiarchive.py
@@ -27,6 +27,14 @@ from dandi.tests.skip import mark
                 version_id=None,
             ),
         ),
+        (
+            "https://gui.dandiarchive.org/#/dandiset/000001/",
+            DandisetURL(
+                api_url=known_instances["dandi"].api,
+                dandiset_id="000001",
+                version_id=None,
+            ),
+        ),
         (
             "https://gui.dandiarchive.org/#/dandiset/000001/0.201104.2302",
             DandisetURL(
@@ -35,6 +43,14 @@ from dandi.tests.skip import mark
                 version_id="0.201104.2302",
             ),
         ),
+        (
+            "https://gui.dandiarchive.org/#/dandiset/000001/0.201104.2302/",
+            DandisetURL(
+                api_url=known_instances["dandi"].api,
+                dandiset_id="000001",
+                version_id="0.201104.2302",
+            ),
+        ),
         (
             "https://gui.dandiarchive.org/#/dandiset/000001/0.201104.2302/files",
             DandisetURL(
['dandi/tests/test_dandiarchive.py', 'dandi/dandiarchive.py']