Fixed bug in AccountInfo::serialize() (#20923)

Closes #20917

(cherry picked from commit edf5bc242c)

Co-authored-by: Eugene Lomov <eugene.v.lomov@gmail.com>

sdk/program/src/account_info.rs

@@ -140,7 +140,7 @@ impl<'a> AccountInfo<'a> {
         bincode::deserialize(&self.data.borrow())
     }
 
-    pub fn serialize_data<T: serde::Serialize>(&mut self, state: &T) -> Result<(), bincode::Error> {
+    pub fn serialize_data<T: serde::Serialize>(&self, state: &T) -> Result<(), bincode::Error> {
         if bincode::serialized_size(state)? > self.data_len() as u64 {
             return Err(Box::new(bincode::ErrorKind::SizeLimit));
         }