docs(button): remove duplicate line in docstrings

Remove duplicate `disabled` line in the Button utility constructor
docstrings.

Author: TomJGooding

src/textual/widgets/_button.py

@@ -398,7 +398,6 @@ def success(
 
         Args:
             label: The text that appears within the button.
-            disabled: Whether the button is disabled or not.
             name: The name of the button.
             id: The ID of the button in the DOM.
             classes: The CSS classes of the button.
@@ -434,7 +433,6 @@ def warning(
 
         Args:
             label: The text that appears within the button.
-            disabled: Whether the button is disabled or not.
             name: The name of the button.
             id: The ID of the button in the DOM.
             classes: The CSS classes of the button.
@@ -470,7 +468,6 @@ def error(
 
         Args:
             label: The text that appears within the button.
-            disabled: Whether the button is disabled or not.
             name: The name of the button.
             id: The ID of the button in the DOM.
             classes: The CSS classes of the button.