Describe the bug
When you open the weakaura options with /wa in-game and have skinning enabled in windtools, you get a lua error.

Additional context

1x ..._WindTools/Modules/Skins/Addons/WeakAurasOptions.lua:487: attempt to call method 'SetBackdrop' (a nil value) [string "@ElvUI_WindTools/Modules/Skins/Addons/WeakAurasOptions.lua"]:487: in function <..._WindTools/Modules/Skins/Addons/WeakAurasOptions.lua:480> [string "=(tail call)"]: ? [string "=[C]"]: in function ShowOptions'
[string "@WeakAurasOptions/WeakAurasOptions.lua"]:612: in function ToggleOptions' [string "@WeakAuras/WeakAuras.lua"]:155: in function OpenOptions'
[string "@WeakAuras/WeakAuras.lua"]:197: in function ?' [string "@FrameXML/ChatFrame.lua"]:5236: in function <FrameXML/ChatFrame.lua:5182> [string "=[C]"]: in function ChatEdit_ParseText'
[string "@FrameXML/ChatFrame.lua"]:4894: in function ChatEdit_SendText' [string "@FrameXML/ChatFrame.lua"]:4930: in function <FrameXML/ChatFrame.lua:4926> [string "=[C]"]: in function ChatEdit_OnEnterPressed'
[string "*ChatFrame.xml:141_OnEnterPressed"]:1: in function <[string "*ChatFrame.xml:141_OnEnterPressed"]:1>

Locals:
self =

{
CreateLowerShadow = defined @ElvUI_WindTools/Modules/Skins/Core.lua:99
TalkingHead = defined @ElvUI_WindTools/Modules/Skins/Blizzard/TalkingHead.lua:6
UpdateShadowColor = defined @ElvUI_WindTools/Modules/Skins/Core.lua:118
HandleMerchantItem = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Merchant.lua:8
ElvUI_AFK = defined @ElvUI_WindTools/Modules/Skins/ElvUI/AFK.lua:7
modules = {
}
CancelTimer = defined @ElvUI_Libraries/Core/Ace3/AceTimer-3.0/AceTimer-3.0.lua:147
GuildInviteFrame = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Guild.lua:6
MirrorTimers = defined @ElvUI_WindTools/Modules/Skins/Blizzard/MirrorTimers.lua:7
RaiderIO = defined @ElvUI_WindTools/Modules/Skins/Addons/RaiderIO.lua:106
SkinCriteriaAlert = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Alerts.lua:63
RaidUtility_ShowButton_OnClick = defined @ElvUI_WindTools/Modules/Skins/ElvUI/RaidUtility.lua:9
Blizzard_LossOfControlFrame_SetUpDisplay = defined @ElvUI_WindTools/Modules/Skins/Blizzard/LossOfControl.lua:6
ElvUI_TotemTracker_Initialize = defined @ElvUI_WindTools/Modules/Skins/ElvUI/TotemTracker.lua:8
Blizzard_WeeklyRewards = defined @ElvUI_WindTools/Modules/Skins/Blizzard/WeeklyRewards.lua:6
OmniCD_Party_ExtraBars = defined @ElvUI_WindTools/Modules/Skins/Addons/OmniCD.lua:40
Blizzard_PlayerChoice = defined @ElvUI_WindTools/Modules/Skins/Blizzard/PlayerChoice.lua:26
SkinItemButton = defined @ElvUI_WindTools/Modules/Skins/Blizzard/ObjectiveTracker.lua:24
UpdateFriendButton = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Friends.lua:9
ADDON_LOADED = defined @ElvUI_WindTools/Modules/Skins/Core.lua:345
WeakAurasIconButton = defined @ElvUI_WindTools/Modules/Skins/Addons/WeakAurasOptions.lua:438
ElvUI_CastBars = defined @ElvUI_WindTools/Modules/Skins/ElvUI/CastBars.lua:59
SettingsPanel = defined @ElvUI_WindTools/Modules/Skins/Blizzard/SettingsPanel.lua:8
TutorialFrame = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Tutorial.lua:6
ElvUI_TotemTracker = defined @ElvUI_WindTools/Modules/Skins/ElvUI/TotemTracker.lua:18
SetEnabledState = defined @Masque/Libs/AceAddon-3.0/AceAddon-3.0.lua:420
Hook = defined @AdiBags/libs/AceHook-3.0/AceHook-3.0.lua:273
enteredLoad = {
}
DressUpFrame = defined @ElvUI_WindTools/Modules/Skins/Blizzard/DressingRoom.lua:6
TomCats_HeaderCollapseButton_SetNormalAtlas = defined @ElvUI_WindTools/Modules/Skins/Addons/TomCats.lua:67
BigWigs_Plugins = defined @ElvUI_WindTools/Modules/Skins/Addons/BigWigs.lua:264
Blizzard_AnimaDiversionUI = defined @ElvUI_WindTools/Modules/Skins/Blizzard/AnimaDiversion.lua:6
UnregisterAllEvents = defined @Masque/Libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:164
Blizzard_ItemInteractionUI = defined @ElvUI_WindTools/Modules/Skins/Blizzard/ItemInteraction.lua:6
Blizzard_ProfessionsCustomerOrders = defined @ElvUI_WindTools/Modules/Skins/Blizzard/ProfessionsCustomerOrders.lua:8
ElvUI_UnitFrames_Construct_AuraBars = defined @ElvUI_WindTools/Modules/Skins/ElvUI/UnitFrames.lua:84
SkinWorldQuestCompleteAlert = defined @ElvUI_WindTools/Modules/Skins/Blizzard/Alerts.lua:174
Wea`