Treating [K${}_4$(H${}_2$O)${}_{0.5}$][SnTe${}_4$] with PPh${}_4^{+}$ or AsPh${}_4^{+}$: Formation of a Highly Air‐Stable Tellurostannate Salt, a Tellurolate with One‐Coordinate Te Atoms, and a Polytelluride Salt with ${}_{\infty }^1$[Te${}_4$(H${}_2$O)${}_2$]${}^{2-}$ Chains