fix: fix total type in paginate (#228)

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##### Checklist
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[x]. -->

- [ ] `npm test` passes
- [ ] tests and/or benchmarks are included
- [ ] documentation is changed or added
- [ ] commit message follows commit guidelines

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##### Description of change
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

- **Bug Fixes**
- Corrected data type for total count in pagination results to ensure
accurate numeric values.

- **Tests**
- Added a test case to verify accurate total count in pagination
results.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

core/dal-runtime/src/DataSource.ts

@@ -77,7 +77,7 @@ export class DataSource<T> implements IDataSource<T> {
     ]);
 
     return {
-      total: ret[1],
+      total: Number(ret[1]),
       pageNum: currentPage,
       rows: ret[0].map(t => TableModelInstanceBuilder.buildInstance(this.tableModel, t)),
     };

core/dal-runtime/test/DataSource.test.ts

@@ -146,5 +146,8 @@ describe('test/Datasource.test.ts', () => {
       $id: insertResult.insertId,
     });
     assert.equal(findRow2, null);
+
+    const res = await dataSource.paginate('findByPrimary', {}, 1, 10);
+    assert(res.total === 0);
   });
 });