Simplify Azure Ai Search Tool (microsoft#6511)

## Why are these changes needed?

Simplified the azure ai search tool and fixed bugs in the code


## Related issue number

"Closes microsoft#6430 " 

## Checks

- [X] I've included any doc changes needed for
<https://microsoft.github.io/autogen/>. See
<https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md> to
build and test documentation locally.
- [X] I've added tests (if relevant) corresponding to the changes
introduced in this PR.
- [X] I've made sure all auto checks have passed.

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

Author: jay-thakur

python/packages/autogen-ext/src/autogen_ext/tools/azure/__init__.py

@@ -4,6 +4,7 @@
     SearchQuery,
     SearchResult,
     SearchResults,
+    VectorizableTextQuery,
 )
 from ._config import AzureAISearchConfig
 
@@ -14,4 +15,5 @@
     "SearchResult",
     "SearchResults",
     "AzureAISearchConfig",
+    "VectorizableTextQuery",
 ]