[Baertram]

The text can be found in the ingamelocalization/localizegeneratestrings.lua files -> constant is :SI_JUMP_TO_GROUP_LEADER_OCCURANCE_PROMPT

    "This group's leader is located in a different version of |cffffff<<1>>|r.\n\nWould you like to travel to their version, which will place you at the wayshrine nearest to them?", -- SI_JUMP_TO_GROUP_LEADER_OCCURANCE_PROMPT

You can search the esoui sources for that constant then:
SI_JUMP_TO_GROUP_LEADER_OCCURANCE_PROMPT

-> playertoplayer.lua, local function OnTravelToLeaderPromptReceived()
lines 767 ff

promptData.messageFormat = GetString(GetUnitZone("player") == groupLeaderZoneName and SI_JUMP_TO_GROUP_LEADER_OCCUR

ANCE_PROMPT or SI_JUMP_TO_GROUP_LEADER_WORLD_PROMPT)

lines 785ff shows where this local function is used:

local function OnUnitCreated(unitTag)
        if ZO_Group_IsGroupUnitTag(unitTag) then
            OnTravelToLeaderPromptReceived()
        end
    end
        local function OnZoneUpdate(unitTag, newZone)
        if ZO_Group_IsGroupUnitTag(unitTag) then
            OnTravelToLeaderPromptReceived()
        end
    end
    local function OnGroupMemberJoined(characterName, displayName, isLocalPlayer)
        if isLocalPlayer then
            local groupLeaderUnitTag = GetGroupLeaderUnitTag()
            if not AreUnitsEqual(groupLeaderUnitTag, "player") then
                pendingJumpToGroupLeaderPrompt = true
                OnTravelToLeaderPromptReceived()
            end
        end
    end
    local function OnPlayerActivateOrLeaderUpdate()
        if pendingJumpToGroupLeaderPrompt then
            OnTravelToLeaderPromptReceived()
        end
    end

As the funcs are local you cannot hack into them directly

But they are registered as event callbacks:

self.control:RegisterForEvent(EVENT_UNIT_CREATED, function(event, ...) OnUnitCreated(...) end)
    self.control:RegisterForEvent(EVENT_ZONE_UPDATE, function(event, ...) OnZoneUpdate(...) end)
    self.control:RegisterForEvent(EVENT_GROUP_MEMBER_JOINED, function(event, ...) OnGroupMemberJoined(...) end)
    self.control:RegisterForEvent(EVENT_LEADER_UPDATE, function(event, ...) OnGroupMemberJoined(...) end)
    self.control:RegisterForEvent(EVENT_GROUP_MEMBER_LEFT, function(event, ...) OnGroupMemberLeft(...) end)

self = ZO_PlayerToPlayer -> object created is PLAYER_TO_PLAYER in func

function ZO_PlayerToPlayer_Initialize(control)
    PLAYER_TO_PLAYER = ZO_PlayerToPlayer:New(control)
end

Try the following in chat as script:

/script PLAYER_TO_PLAYER.control:UnregisterForEvent(EVENT_GROUP_MEMBER_JOINED)

Or try one of the others like EVENT_UNIT_CREATED

But beware: This might damage the grouping tools and other addons!

Another approach would be to prehook the function self:AddPromptToIncomingQueue which is used in OnTravelToLeaderPromptReceived()
self = PLAYER_TO_PLAYER again

The function starts in line 1075

function ZO_PlayerToPlayer:AddPromptToIncomingQueue(interactType, characterName, displayName, targetLabel, acceptCallback, declineCallback, deferDecisionCallback)

Just add something like

ZO_PreHook(PLAYER_TO_PLAYER, "AddPromptToIncomingQueue", function(interactType, characterName, displayName, targetLabel, acceptCallback, declineCallback, deferDecisionCallback)
 if interactType == INTERACT_TYPE_TRAVEL_TO_LEADER then return true end
--return true will exit here adn NOT call the original code after that
end)