SafeSetFont: skip the text re-render for secret text entirely

Align with the 12.1 branch's independently-developed fix for the same
taint bug: gate on issecretvalue before any boolean use of the text
instead of doing the SetText round trip on secrets. Secret-text
fontstrings rewrite on every update, so the font change still lands on
the next natural SetText. Keeps the two branches' SafeSetFont identical.

Author: mergetest

Config.lua

@@ -767,15 +767,18 @@ function DF:SafeSetFont(fontString, fontNameOrPath, fontSize, outline)
             -- This is needed because switching between font families with different outline flags
             -- may not immediately update the rendered text without a text refresh
             -- Note: the text may be a SECRET string (native cooldown countdown
-            -- text, health text, ...). Truthiness on a secret is allowed, but a
-            -- value comparison (~= "") is BLOCKED — and even inside pcall each
-            -- blocked compare logs a DandersFrames taint incident (hundreds per
-            -- minute in PvP instances; bugs #987/#988). GetText() returns nil,
-            -- never "", for empty text, so truthiness is also the complete
-            -- check. SetText accepts secret strings, so the round trip is safe.
+            -- text, health text, unit names in combat). COMPARING a secret
+            -- (text ~= "") is BLOCKED, and each blocked compare logs a
+            -- DandersFrames taint incident even inside pcall — bugs #987/#988
+            -- (hundreds/minute in PvP instances). Skip the re-render for secret
+            -- text: issecretvalue runs BEFORE any boolean use of the value, and
+            -- secret-text fontstrings rewrite on every update anyway, so the
+            -- font change lands on the next natural SetText. The old `~= ""`
+            -- guard is dropped as redundant — GetText() returns nil, never "",
+            -- for empty text. (Kept identical to the 12.1 branch's version.)
             pcall(function()
                 local text = fontString:GetText()
-                if text then
+                if not (issecretvalue and issecretvalue(text)) and text then
                     fontString:SetText("")
                     fontString:SetText(text)
                 end