fix: Fix search for s3 datasources (#25835)

When the column field is an empty array, it breaks searching, this PR
fixes that issue.


Fixes #25540 

## Testing
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#### How Has This Been Tested?
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- [x] Manual
- [ ] Jest
- [ ] Cypress
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#### Test Plan
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#### Issues raised during DP testing
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## Checklist:
#### Dev activity
- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
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- [ ] I have added tests that prove my fix is effective or that my
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#### QA activity:
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app/client/src/pages/Editor/Explorer/Datasources/DatasourceStructureContainer.tsx

@@ -116,6 +116,10 @@ const Container = (props: Props) => {
     const list: string[] = [];
 
     props.datasourceStructure.tables.map((table) => {
+      // if the column is empty push the table name alone.
+      if (table.columns.length === 0) {
+        list.push(`${table.name}~`);
+      }
       table.columns.forEach((column) => {
         list.push(`${table.name}~${column.name}`);
       });
@@ -139,7 +143,7 @@ const Container = (props: Props) => {
     flatStructure.forEach((structure) => {
       const segments = structure.split("~");
       // if the value is present in the columns, add the column and its parent table.
-      if (segments[1].toLowerCase().includes(value)) {
+      if (!!segments[1] && segments[1].toLowerCase().includes(value)) {
         tables.add(segments[0]);
         columns.add(segments[1]);
         return;