Resolves the importer config.json path from the CONFIG_PATH env var,
falling back to the container default when the variable is unset, empty,
or whitespace-only. A blank override is treated as absent so callers never
receive an unusable empty path; a surrounding-whitespace value is trimmed.
Returns string
Absolute path to config.json (credentials.json is its sibling).
Resolves the importer config.json path from the
CONFIG_PATHenv var, falling back to the container default when the variable is unset, empty, or whitespace-only. A blank override is treated as absent so callers never receive an unusable empty path; a surrounding-whitespace value is trimmed.