fix(ci): filter structural XML elements from property detection

When a new dependency is added to parent/pom.xml, the diff contains
structural XML elements like <groupId>, <artifactId>, <version> which
were incorrectly extracted as "changed properties" by detectChangedProperties.

This caused the script to search for modules using ${artifactId} or
${groupId} as property references, which either matched nothing useful
or caused spurious failures.

Fix: filter out known structural POM element names (groupId, artifactId,
version, scope, type, etc.) so only actual property names like
"pgvector-version" or "openai-java-version" are detected.

Fixes the CI script bug seen in PR #22207 where adding a new component
to parent/pom.xml caused the dependency detection to fail.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: gnodet

.github/actions/incremental-build/incremental-build.sh

@@ -104,13 +104,19 @@ extractPomDiff() {
 
 # Detect which properties changed in a pom.xml diff.
 # Returns one property name per line.
+# Filters out structural XML elements (groupId, artifactId, version, etc.)
+# to only return actual property names (e.g. openai-java-version).
 detectChangedProperties() {
   local diff_content="$1"
 
+  # Known structural POM elements that are NOT property names
+  local structural_elements="groupId|artifactId|version|scope|type|classifier|optional|systemPath|exclusions|exclusion|dependency|dependencies|dependencyManagement|parent|modules|module|packaging|name|description|url|relativePath"
+
   echo "$diff_content" | \
     grep -E '^[+-][[:space:]]*<[^>]+>[^<]*</[^>]+>' | \
     grep -vE '^\+\+\+|^---' | \
     sed -E 's/^[+-][[:space:]]*<([^>]+)>.*/\1/' | \
+    grep -vE "^(${structural_elements})$" | \
     sort -u || true
 }