Remove incorrectly typed dcterms:date from DOSDP pattern.

The cyclingCellStates.yaml DOSDP pattern inserts a dcterms:date
annotation, but formats it as a xsd:string rather than as a xsd:dateTime
-- this is apparently a limitation of the DOSDP tooling (correctly
setting the var slot type to xsd:dateTime does _not_ fix the issue).

We remove that annotation until the DOSDP tools are capable to correctly
deal with non-string slots.

Those violations should have been caught by the
illegal-date-violation.sparql check -- they were not because the ODK
only runs those checks on the (preprocessed) edit file without merging
the components (including the pattern-derived definitions.owl file),
whose contents is therefore not covered by those checks -- I believe
this is a ODK bug.

src/patterns/dosdp-patterns/cyclingCellStates.yaml

@@ -18,7 +18,6 @@ annotationProperties:
   xref: "oio:hasDbXref"
   contributor: "http://purl.org/dc/terms/contributor"
   hasExactSynonym: "oio:hasExactSynonym"
-  date: "http://purl.org/dc/terms/date"
 
 vars:
   cell: "'cell'"
@@ -28,9 +27,6 @@ data_list_vars:
   synonym_xrefs: "xsd:string"
   # Use this for recording reference using PMID/DOIS
 
-data_vars:
-  date_created: "xsd:string"
-
 name:
   text: "cycling %s"
   vars:
@@ -59,7 +55,3 @@ equivalentTo:
 annotations:
   - annotationProperty: contributor
     var: creator
-  - annotationProperty: date
-    text: "%s"
-    vars:
-      - date_created