Application of initial desert heat is instantaneous

[halogod35]

When walking into the desert heat, you instantly take damage from no waterskin as opposed the timer starting the second you walk into desert heat.

[MatthewBishop]

We need to change the delay here

https://github.com/2006-Scape/2006Scape/blob/master/2006Scape%20Server/src/main/java/com/rs2/game/content/traveling/DesertHeat.java#L111

Per https://oldschool.runescape.wiki/w/Desert_heat the duration between heat damage is variable. See #594 for another desert bug.