fix: fix typo Update node.rs (#3176)

## Motivation

I noticed a typo in the word "ceritifcates" and corrected it to
"certificates".

Signed-off-by: Dmitry <98899785+mdqst@users.noreply.github.com>

linera-core/src/node.rs

@@ -219,7 +219,7 @@ pub enum NodeError {
     #[error("We don't have the value for the certificate.")]
     MissingCertificateValue,
 
-    #[error("Response doesn't contain requested ceritifcates: {0:?}")]
+    #[error("Response doesn't contain requested certificates: {0:?}")]
     MissingCertificates(Vec<CryptoHash>),
 
     #[error("Validator's response to block proposal failed to include a vote")]