Remove preemptive warning messages for unproxyable members

The member length limit is now long enough that it's unlikely to
hit the cap by accident. An error will still be displayed if you
attempt to perform a message proxy.

PluralKit.Core/Models.cs

@@ -19,9 +19,6 @@ namespace PluralKit
         [JsonIgnore] public string Token { get; set; }
         [JsonProperty("created")] public Instant Created { get; set; }
         [JsonProperty("tz")] public string UiTz { get; set; }
-
-        [JsonIgnore] public int MaxMemberNameLength => Tag != null ? Limits.MaxProxyNameLength - Tag.Length - 1 : Limits.MaxProxyNameLength;
-
         [JsonIgnore] public DateTimeZone Zone => DateTimeZoneProviders.Tzdb.GetZoneOrNull(UiTz);
     }