[lvgl] Migrate to 9.6.0 (#20257)

Co-authored-by: Claude <noreply@anthropic.com>

platformio.ini

@@ -108,7 +108,7 @@ build_unflags =
 lib_deps =
     esphome/dlms_parser@2.2.0             ; dlms_meter
     bblanchon/ArduinoJson@7.4.3           ; json
-    lvgl/lvgl@9.5.0                       ; lvgl
+    lvgl/lvgl@9.6.0                       ; lvgl
 
 ; This are common settings for the ESP8266 using Arduino.
 [common:esp8266-arduino]
@@ -646,7 +646,7 @@ extends = common
 platform = platformio/native
 lib_deps =
     esphome/noise-c@0.1.31  ; used by noise (api, ota)
-    lvgl/lvgl@9.5.0         ; lvgl
+    lvgl/lvgl@9.6.0         ; lvgl
 build_flags =
     ${common.build_flags}
     -DUSE_HOST