A student prepares a galvanic cell at \(298\text{ K}\) based on the following standard reaction:
\[ \text{Zn}(s) + 2\,\text{Ag}^+(aq) \rightleftharpoons \text{Zn}^{2+}(aq) + 2\,\text{Ag}(s) \quad E^\circ_{\text{cell}} = +1.56\text{ V} \]
The student uses a beaker containing a zinc strip in \(1.0\text{ M Zn(NO}_3)_2(aq)\) as the anode half-cell and a beaker containing a silver strip in \(1.0\text{ M AgNO}_3(aq)\) as the cathode half-cell. Instead of using a salt bridge saturated with \(\text{KNO}_3(aq)\), the student mistakenly uses a salt bridge saturated with \(\text{KCl}(aq)\). Upon inserting the bridge, a white precipitate forms immediately around the tip in the cathode compartment, and the initial measured cell potential is noticeably lower than \(+1.56\text{ V}\). Which of the following best explains why the cell potential is lower than \(E^\circ_{\text{cell}}\)?