experimental re-embedding (#1186)

* first cut at re-embedding route and back-end support

* update and expand config route tests

* add scanpy_umap

* add reembedding to config route parameters

* front-end support for reembedding fetch and UI

* remove unused imports

* add loading state

* save reembedding in reducer state

* improve withColsFrom

* transmit reembed schema to client; pick unique embedding names

* display embeddings

* format

* lint

* spaces, tab size 2

* lint

* test hack for smoke-test race

* back out hack sleep

* add check for backed mode

* add unit test for reembedding

* lint

* hide re-embedding CLI param from help

server/data_cxg/cxg_adaptor.py

@@ -164,6 +164,9 @@ class CxgAdaptor(DataAdaptor):
         array = self.open_array(f"emb/{ename}")
         return array[:, 0:dims]
 
+    def compute_embedding(self, method, filter):
+        raise NotImplementedError("CXG does not yet support re-embedding")
+
     def get_X_array(self, obs_mask=None, var_mask=None):
         obs_items = self._convert_mask(obs_mask)
         var_items = self._convert_mask(var_mask)