Migrate feature-format-matrix test files to new metadata structure

Update remaining tests-on-ci uses in feature-format-matrix to
tests.run.ci.

Author: cderv

dev-docs/feature-format-matrix/qmd-files/crossref/float/custom/document.qmd

@@ -8,7 +8,9 @@ crossref:
 format:
   docusaurus-md: {}
 _quarto:
-  tests-on-ci: false 
+  tests:
+    run:
+      ci: false 
 ---
 
 ::: {#dia-1}

dev-docs/feature-format-matrix/qmd-files/mermaid/document.qmd

@@ -3,7 +3,9 @@ title: Mermaid
 format: 
   docusaurus-md: {}
 _quarto:
-  tests-on-ci: false 
+  tests:
+    run:
+      ci: false 
 ---
 
 ::: {.content-visible when-format="docusaurus-md"}