update branch creation validation condition

Author: solababs

backend/infrahub/core/branch/models.py

@@ -85,13 +85,18 @@ def validate_branch_name(cls, value: str) -> str:
     @model_validator(mode="after")
     def validate_name(self) -> Self:
         if (
-            not self.sync_with_git
-            and config.SETTINGS.git.sync_branch_names
-            and not branch_name_in_sync_branches(branch_short_name=self.name)
+            not config.SETTINGS.git.sync_branch_names
+            or self.name == GLOBAL_BRANCH_NAME
+            or self.is_default
+            or self.sync_with_git
         ):
+            return self
+
+        if not branch_name_in_sync_branches(branch_short_name=self.name):
             raise ValidationError(
                 f"Branch name '{self.name}' does not match sync branch names {config.SETTINGS.git.sync_branch_names}"
             )
+
         return self
 
     @field_validator("branched_from", mode="before")