fix(perplexity): silence mypy union-attr after dropping None guards

After removing the redundant 'if self._client is None: raise RuntimeError'
blocks, mypy can no longer narrow the type since warm_up()'s side effect
is invisible to it. Add # type: ignore[union-attr] on the .post() calls
in run / run_async (per sjrl review).

Author: jliounis

integrations/perplexity/src/haystack_integrations/components/websearch/perplexity/perplexity_websearch.py

@@ -128,7 +128,7 @@ def run(
         if self._client is None:
             self.warm_up()
 
-        response = self._client.post(
+        response = self._client.post(  # type: ignore[union-attr]
             PERPLEXITY_SEARCH_URL,
             headers=self._build_headers(),
             json=self._build_body(query, search_params),
@@ -156,7 +156,7 @@ async def run_async(
         if self._async_client is None:
             self.warm_up()
 
-        response = await self._async_client.post(
+        response = await self._async_client.post(  # type: ignore[union-attr]
             PERPLEXITY_SEARCH_URL,
             headers=self._build_headers(),
             json=self._build_body(query, search_params),