[github] Enable TINT_ENABLE_INSTALL on CI

This ensures that the Tint executable is included in the prebuilt
binary releases.

No-Try: true
Change-Id: I36f6198c9dbcc8455868e89b4f9f6bc62d8e5d1b
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/320035
Auto-Submit: James Price <jrprice@google.com>
Commit-Queue: Natalie Chouinard <chouinard@google.com>
Reviewed-by: Natalie Chouinard <chouinard@google.com>

.github/workflows/dawn-ci.cmake

diff --git a/.github/workflows/dawn-ci.cmake b/.github/workflows/dawn-ci.cmake
index 4c15886..0bfb4de 100644
--- a/.github/workflows/dawn-ci.cmake
+++ b/.github/workflows/dawn-ci.cmake
@@ -7,6 +7,7 @@
 endif ()
 set(DAWN_FETCH_DEPENDENCIES ON CACHE BOOL "")
 set(DAWN_ENABLE_INSTALL ON CACHE BOOL "")
+set(TINT_ENABLE_INSTALL ON CACHE BOOL "")
 if (CMAKE_SYTEM_NAME STREQUAL "Linux")
     # `sccache` seems effective only on linux.
     # for windows, we could look into `buildcache`