Reorder TL eligibility message: action before caution (facebook#5146)

Summary:
Pull Request resolved: facebook#5146

Apply self-review suggestion from D97489418: move the actionable
instructions (UI button / `Client.add_transferable_experiment`) before
the caution text so users see what to do first, then the warning.

Cleaned-up version of D97553476 — excludes accidental merge changes to
generation_node.py and test_generation_node.py.

Reviewed By: shrutipatel31

Differential Revision: D99385259

fbshipit-source-id: 532fc945e00991b4d40ef6c3c89518fd3142fe2f

Author: Lena Kashtelyan

ax/analysis/healthcheck/transfer_learning_analysis.py

@@ -170,14 +170,14 @@ def compute(
             f"**{n} eligible source experiment(s)** "
             "for transfer learning:\n\n"
             f"{exp_lines}\n\n"
-            "Caution: Only use source experiments that are closely related "
-            "to your current experiment. "
-            "Using data from unrelated experiments can lead to negative "
-            "transfer, which may hurt "
-            "optimization performance. Review the overlapping parameters "
-            "before enabling transfer learning. If using the UI, 'Learn from "
+            "If using the UI, 'Learn from "
             "Related Experiments' button is likely available for use; "
-            "otherwise, use `Client.add_transferable_experiment`."
+            "otherwise, use `Client.add_transferable_experiment`.\n\n"
+            "Caution: Only use source experiments that are closely related "
+            "to your current experiment. Using data from unrelated experiments "
+            "can lead to negative transfer, which may hurt optimization "
+            "performance. Review the overlapping parameters before enabling "
+            "transfer learning."
         )
 
         return TransferLearningAnalysisCard(