fix: preserve GarminConnectTooManyRequestsError through login exception handler

The bare except Exception block was catching and re-wrapping 429 errors
from client.login() as GarminConnectConnectionError, hiding the real type
from callers. Re-raise TooManyRequests and AuthenticationError directly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: cyberjunky

garminconnect/__init__.py

@@ -709,9 +709,9 @@ def login(self, /, tokenstore: str | None = None) -> tuple[str | None, str | Non
             raise GarminConnectConnectionError(f"Login failed: {e}") from e
         except FileNotFoundError:
             raise
+        except (GarminConnectTooManyRequestsError, GarminConnectAuthenticationError):
+            raise
         except Exception as e:
-            if isinstance(e, GarminConnectAuthenticationError):
-                raise
             error_str = str(e).lower()
             auth_indicators = ["401", "unauthorized", "authentication", "login failed"]
             if any(indicator in error_str for indicator in auth_indicators):