fix(useDataSource): state mutations in computed getters should be avoided

[xachary]

General

fix about this warnging:
[Vue warn] Computed is still dirty after getter evaluation, likely because a computed is mutating its own dependency in its getter. State mutations in computed getters should be avoided.

Compute should not change own dependencies`s values!

Keep original the type of getDataSourceRef

• Pull request template structure not broken

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