Remove build directory exclusion from gcovr config (#1640)

Remove exclusion of the build directory from coverage.

Author: baylesj

gcovr.cfg

@@ -9,9 +9,6 @@ merge-mode-functions = separate
 filter = src/lib_json/
 filter = include/json/
 
-# Exclude the build directory to avoid processing generated files
-exclude-directories = build
-
 # --- Noise Reduction ---
 # Ignore branches that are generated by the compiler (e.g., exception handling)
 # This drastically reduces "false positives" for missing branch coverage.