utils.js: remove C4 diagram

Author: thypon

src/utils.js

@@ -14,10 +14,6 @@ Desired format:
 ### Changes
 <list_of_changes> // Describe the main changes in the PR, organizing them by filename
 
-\`\`\`mermaid
-<c4_diagram> // Generate a C4 diagram in mermaid format for the PR included
-\`\`\`
-
 \`\`\`mermaid
 <sequence_diagram> // Generate a sequence diagram in mermaid format for the PR included
 \`\`\`