Fix flaky grbs007 clickData race; mark dvcv003 flaky

grbs007: the clickData callback also fires on load with clickData=None,
setting the textarea to "null". The test read the value right after the
click and raced that initial value - data != "" passed but json.loads
returned None. Wait for the real click payload before parsing.

dvcv003: the devtools error overlay intermittently reports an empty
error title under React 19; mark it @flaky(max_runs=3), matching the
existing convention for these overlay tests in this file (dvcv013).

Author: T4rk1n

components/dash-core-components/tests/integration/graph/test_graph_basics.py

@@ -365,7 +365,16 @@ def handleClick(clickData):
 
     dash_dcc.find_elements("g .xy")[0].click()
 
-    data = dash_dcc.wait_for_element("#test-text-area").get_attribute("value")
+    # The clickData callback also fires once on load with clickData=None (value
+    # "null"); wait for the click's real payload before parsing, otherwise we
+    # race that initial value and json.loads returns None.
+    wait.until(
+        lambda: (dash_dcc.find_element("#test-text-area").get_attribute("value") or "")
+        not in ("", "null"),
+        timeout=3,
+    )
+
+    data = dash_dcc.find_element("#test-text-area").get_attribute("value")
     assert data != "", "graph clickData must contain data"
 
     data = json.loads(data)

tests/integration/devtools/test_callback_validation.py

@@ -140,6 +140,7 @@ def x(a):
     check_errors(dash_duo, specs)
 
 
+@flaky(max_runs=3)
 def test_dvcv003_duplicate_outputs_same_callback(dash_duo):
     app = Dash(__name__)
     app.layout = html.Div([html.Div(id="a"), html.Div(id="b")])