DpCatalog: move constructor body off the signature line

Addresses CodeQL "More than one statement per line" alert introduced by
the previous commit, which collapsed the constructor signature and the
empty body onto the same line. Adds an explanatory comment inside the
body to keep it on its own line; clang-format would otherwise re-collapse
the empty `{}` under the repo's Chromium-based style.

Behavior unchanged.

Author: carlosvales

Svc/DpCatalog/DpCatalog.cpp

@@ -21,7 +21,9 @@ static_assert(DP_MAX_FILES > 0, "Configuration DP_MAX_FILES must be positive");
 // Component construction and destruction
 // ----------------------------------------------------------------------
 
-DpCatalog ::DpCatalog(const char* const compName) : DpCatalogComponentBase(compName) {}
+DpCatalog ::DpCatalog(const char* const compName) : DpCatalogComponentBase(compName) {
+    // Members are default-initialized via in-class initializers in the header.
+}
 
 void DpCatalog::configure(Fw::FileNameString directories[DP_MAX_DIRECTORIES],
                           FwSizeType numDirs,