Fix markdown rendering on dag docs

Author: aritra24

airflow-core/src/airflow/ui/src/pages/Dag/Header.tsx

@@ -94,7 +94,10 @@ export const Header = ({
               <DisplayMarkdownButton
                 header="Dag Documentation"
                 icon={<FiBookOpen />}
-                mdContent={dag.doc_md}
+                mdContent={dag.doc_md
+                  .split("\n")
+                  .map((str) => str.trimStart())
+                  .join("\n")}
                 text="Dag Docs"
               />
             )}

airflow-core/src/airflow/ui/src/pages/Task/Header.tsx

@@ -30,7 +30,10 @@ export const Header = ({ task }: { readonly task: TaskResponse }) => (
         <DisplayMarkdownButton
           header="Task Documentation"
           icon={<FiBookOpen />}
-          mdContent={task.doc_md}
+          mdContent={task.doc_md
+            .split("\n")
+            .map((str) => str.trimStart())
+            .join("\n")}
           text="Task Docs"
         />
       )