Increase max sql-over-http response size from 1MB to 10MB (#4961)

## Problem

1MB response limit is very small.

## Summary of changes

This data is not yet tracked, so we shoudn't raise the limit too high yet. 
But as discussed with @kelvich and @conradludgate, this PR lifts it to 
10MB, and adds also details of the limit to the error response.

proxy/src/http/sql_over_http.rs

@@ -34,7 +34,7 @@ enum Payload {
     Batch(Vec<QueryData>),
 }
 
-pub const MAX_RESPONSE_SIZE: usize = 1024 * 1024; // 1 MB
+pub const MAX_RESPONSE_SIZE: usize = 10 * 1024 * 1024; // 10 MB
 const MAX_REQUEST_SIZE: u64 = 1024 * 1024; // 1 MB
 
 static RAW_TEXT_OUTPUT: HeaderName = HeaderName::from_static("neon-raw-text-output");
@@ -214,7 +214,7 @@ pub async fn handle(
 
     if request_content_length > MAX_REQUEST_SIZE {
         return Err(anyhow::anyhow!(
-            "request is too large (max {MAX_REQUEST_SIZE} bytes)"
+            "request is too large (max is {MAX_REQUEST_SIZE} bytes)"
         ));
     }
 
@@ -292,13 +292,15 @@ async fn query_to_json<T: GenericClient>(
     // big.
     pin_mut!(row_stream);
     let mut rows: Vec<tokio_postgres::Row> = Vec::new();
-    let mut curret_size = 0;
+    let mut current_size = 0;
     while let Some(row) = row_stream.next().await {
         let row = row?;
-        curret_size += row.body_len();
+        current_size += row.body_len();
         rows.push(row);
-        if curret_size > MAX_RESPONSE_SIZE {
-            return Err(anyhow::anyhow!("response too large"));
+        if current_size > MAX_RESPONSE_SIZE {
+            return Err(anyhow::anyhow!(
+                "response is too large (max is {MAX_RESPONSE_SIZE} bytes)"
+            ));
         }
     }