fix: Catch error when computing relative filepath for serialization

Author: pawamoy

src/griffe/_internal/models.py

@@ -1288,7 +1288,6 @@ def as_dict(self, *, full: bool = False, **kwargs: Any) -> dict[str, Any]:
                 {
                     "path": self.path,
                     "filepath": self.filepath,
-                    "relative_filepath": self.relative_filepath,
                     "relative_package_filepath": self.relative_package_filepath,
                     "is_public": self.is_public,
                     "is_deprecated": self.is_deprecated,
@@ -1316,6 +1315,9 @@ def as_dict(self, *, full: bool = False, **kwargs: Any) -> dict[str, Any]:
                 },
             )
 
+            with suppress(ValueError):
+                base["relative_filepath"] = self.relative_filepath
+
             if "source_link" not in base and (source_link := self.source_link) is not None:
                 base["source_link"] = source_link