docs: fixed minor misspelling in harnesses guide (#23547)

Author: navdbaloch

guides/using-component-harnesses.md

@@ -251,7 +251,7 @@ harnesses, you avoid depending on internal DOM structure directly.
 
 In addition to DOM structure, component asynchronicity often offers a challenge when updating
 components. If a component changes between synchronous and asynchronous, downstream unit tests may
-break do to expectations around timing. Tests then require the addition or removal of some
+break due to expectations around timing. Tests then require the addition or removal of some
 arcane combination of `whenStable`, `flushMicroTasks`, `tick`, or `detectChanges`. Component
 harnesses, however, avoid this problem by normalizing the asynchronicity of all component behaviors 
 with all asynchronous APIs. When a test uses these harnesses, changes to asynchronicity become