[Export] Allow using ICU data from export templates instead of editor embedded data.

thirdparty/README.md

@@ -420,7 +420,7 @@ Files extracted from upstream source:
 
 Files generated from upstream source:
 
-- The `icudt76l.dat` built with the provided `godot_data.json` config file (see
+- The `icudt_godot.dat` built with the provided `godot_data.json` config file (see
   https://github.com/unicode-org/icu/blob/master/docs/userguide/icu_data/buildtool.md
   for instructions).
 
@@ -430,7 +430,7 @@ Files generated from upstream source:
 3. Reconfigure ICU with custom data config:
    `ICU_DATA_FILTER_FILE={GODOT_SOURCE}/thirdparty/icu4c/godot_data.json ./runConfigureICU {PLATFORM} --with-data-packaging=common`
 4. Delete `data/out` folder and rebuild data: `cd data && rm -rf ./out && make`
-5. Copy `source/data/out/icudt76l.dat` to the `{GODOT_SOURCE}/thirdparty/icu4c/icudt76l.dat`
+5. Copy `source/data/out/icudt{ICU_VERSION}l.dat` to the `{GODOT_SOURCE}/thirdparty/icu4c/icudt_godot.dat`
 
 
 ## jolt_physics