Remove SSO_PAGE_HEADERS from login POST and MFA verify

PR #215 re-introduced browser headers on the login POST and MFA
verify endpoints. These are mobile API endpoints that expect the
default GCM-iOS user agent — browser headers cause 401/429 from
Garmin. Same regression as 0.7.7, fixed in 0.7.8, re-introduced
in 0.7.10.

Browser headers should ONLY be on page requests (sign-in, embed).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: matin

src/garth/sso.py

@@ -118,7 +118,6 @@ def login(
         "sso",
         "/mobile/api/login",
         params=login_params,
-        headers=SSO_PAGE_HEADERS,
         json={
             "username": email,
             "password": password,
@@ -218,7 +217,6 @@ def handle_mfa(
         "sso",
         "/mobile/api/mfa/verifyCode",
         params=login_params,
-        headers=SSO_PAGE_HEADERS,
         json={
             "mfaMethod": mfa_method,
             "mfaVerificationCode": mfa_code,

src/garth/version.py

@@ -1 +1 @@
-__version__ = "0.7.11"
+__version__ = "0.7.12"