No, the title is not an advertisement for a feature on a new television set. There were no mute buttons in Romantic England.
"Mutability" means "the ability to change," but the word does not appear anywhere in the main text of the poem. The title lets us know that all the talk about "dissolution" really has to do with time and change. For fans of literary history, the title is also a sign that Wordsworth is tapping into a traditional theme, or trope, that has been explored by other writers before him. Sophisticated English readers in Wordsworth’s age would have recognized an allusion to Edmund Spenser’s The Fairie Queene and its famous "Mutabilitie Cantos."