chore: Change trace payload size limit from 3.2 MiB to 3.2 MB (#763)

Change trace payload size limit from 3.2 MiB (3.2 * 1024 * 1024) to 3.2
MB (3.2 * 1000 * 1000) because that's more commonly used in the
codebase.
https://github.com/search?q=org%3ADataDog%203200000&type=code

Author: lym953

bottlecap/src/traces/trace_aggregator.rs

@@ -5,7 +5,7 @@ use std::collections::VecDeque;
 /// that the Datadog Trace API accepts. The value is 3.2 MB.
 ///
 /// <https://github.com/DataDog/datadog-agent/blob/9d57c10a9eeb3916e661d35dbd23c6e36395a99d/pkg/trace/writer/trace.go#L27-L31>
-pub const MAX_CONTENT_SIZE_BYTES: usize = (32 * 1_024 * 1_024) / 10;
+pub const MAX_CONTENT_SIZE_BYTES: usize = 3_200_000;
 
 // Bundle SendDataBuilder with payload size because SendDataBuilder doesn't
 // expose a getter for the size