Update TemplateProcessor should replace blocks in footers and headers too

[damienfa]

Description

This PR fixes an issue where the replaceXmlBlock() method only searched for and replaced macros in the main document part, ignoring headers and footers.

Fixes # (issue)

The replaceXmlBlock() method was limited to replacing XML blocks only in tempDocumentMainPart. When templates contained macros in headers or footers that needed to be replaced with complex XML blocks (such as images, charts, or formatted content), these replacements would silently fail.

This change brings replaceXmlBlock() in line with other replacement methods like setValue() and setImageValue(), which already search across all document parts. This ensures consistent behavior across the API and allows users to replace complex content in headers and footers, which is a common requirement when working with Word templates.

Checklist:

• My CI is 🟢
• I have covered by unit tests my new code (check build/coverage for coverage report)
• I have updated the documentation to describe the changes
• I have updated the changelog