Merged PR 4867: eng | Update patch version for release MDS 3.1.7

#### AI description  (iteration 1)
#### PR Classification
Version update for release.

#### PR Summary
This pull request updates the patch version for the MDS 3.1.7 release.
- `eng/pipelines/libraries/mds-variables.yml`: Incremented the patch version from 6 to 7.

Related work items: #29493

eng/pipelines/libraries/mds-variables.yml

@@ -12,7 +12,7 @@ variables:
   - name: Minor
     value: 1
   - name: Patch
-    value: 6
+    value: 7
 
   - name: NugetPackageVersion
     value: $(Major).$(Minor).$(Patch)