[Dridzt]

Create a folder:
NoEscape

Inside it create 2 text files:
NoEscape.toc
NoEscape.lua

Open them in turn with a text editor and copy the following:
NoEscape.toc

## Interface: 40000
## Title: NoEscape
## Notes: Disables ESC for some static popup dialogs.

NoEscape.lua

NoEscape.lua

local ESC_DISABLED = {
    "RESURRECT",
    "RESURRECT_NO_SICKNESS",
    "RESURRECT_NO_TIMER",
    "SKINNED_REPOP",
    "CONFIRM_SUMMON",
    "BFMGR_INVITED_TO_QUEUE_WARMUP",
    "BFMGR_INVITED_TO_QUEUE",
    "BFMGR_INVITED_TO_ENTER",
    "ARENA_TEAM_INVITE",
    "PARTY_INVITE",
}

for i,v in ipairs(ESC_DISABLED) do
    StaticPopupDialogs[v].hideOnEscape = nil
end

Save the files and copy the whole folder into \World of Warcraft\Interface\AddOns\

If you want to keep the Esc to cancel behavior for some of those dialogs
just put a -- infront of the dialog name
example:

-- "PARTY_INVITE",

to leave the group invite dialog unmodified.

Completely drycoded and untested so use at your own risk.