[Exporter.Prometheus] remove redundant if in WriteUnicodeNoEscape (#6077

)

Co-authored-by: Piotr Kiełkowicz <pkiekowicz@splunk.com>
Co-authored-by: Mikel Blanchard <mblanchard@macrosssoftware.com>

src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusSerializer.cs

@@ -102,16 +102,13 @@ public static int WriteUnicodeNoEscape(byte[] buffer, int cursor, ushort ordinal
             buffer[cursor++] = unchecked((byte)(0b_1100_0000 | (ordinal >> 6)));
             buffer[cursor++] = unchecked((byte)(0b_1000_0000 | (ordinal & 0b_0011_1111)));
         }
-        else if (ordinal <= 0xFFFF)
+        else
         {
+            // all other <= 0xFFFF which is ushort.MaxValue
             buffer[cursor++] = unchecked((byte)(0b_1110_0000 | (ordinal >> 12)));
             buffer[cursor++] = unchecked((byte)(0b_1000_0000 | ((ordinal >> 6) & 0b_0011_1111)));
             buffer[cursor++] = unchecked((byte)(0b_1000_0000 | (ordinal & 0b_0011_1111)));
         }
-        else
-        {
-            Debug.Assert(ordinal <= 0xFFFF, ".NET string should not go beyond Unicode BMP.");
-        }
 
         return cursor;
     }