[Data Explorer] Removed X icon in data source selection. (#5238)

* removed X icon in data source selection.

Signed-off-by: Abhilash <abhilash.bhimanna@senecaglobal.com>

* updated changelog

Signed-off-by: Abhilash <abhilash.bhimanna@senecaglobal.com>

* Update CHANGELOG.md

Signed-off-by: Miki <amoo_miki@yahoo.com>

---------

Signed-off-by: Abhilash <abhilash.bhimanna@senecaglobal.com>
Signed-off-by: Ashwin P Chandran <ashwinpc@amazon.com>
Signed-off-by: Miki <amoo_miki@yahoo.com>
Co-authored-by: Abhilash <abhilash.bhimanna@senecaglobal.com>
Co-authored-by: Ashwin P Chandran <ashwinpc@amazon.com>
Co-authored-by: Miki <amoo_miki@yahoo.com>
(cherry picked from commit df08387)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

# Conflicts:
#	CHANGELOG.md

src/plugins/data/public/data_sources/datasource_selector/datasource_selectable.tsx

@@ -128,6 +128,7 @@ export const DataSourceSelectable = ({
       selectedOptions={selectedSources as any}
       onChange={handleSourceChange}
       singleSelection={singleSelection}
+      isClearable={false}
       async
     />
   );