librenderengine: avoid vector<const T>

A container of const T uses std::allocator<const T>, which was an
undocumented libc++ extension that has been removed.

See https://github.com/llvm/llvm-project/pull/96319.

Bug: 349681543
Test: m librenderengine
Change-Id: I4c0f5adb94415777f832217bc8115e04de6186c5
diff --git a/libs/renderengine/skia/Cache.cpp b/libs/renderengine/skia/Cache.cpp
index abe0d9b..7b3b176 100644
--- a/libs/renderengine/skia/Cache.cpp
+++ b/libs/renderengine/skia/Cache.cpp
@@ -718,8 +718,7 @@
         const auto externalTexture =
                 std::make_shared<impl::ExternalTexture>(externalBuffer, *renderengine,
                                                         impl::ExternalTexture::Usage::READABLE);
-        std::vector<const std::shared_ptr<ExternalTexture>> textures =
-            {srcTexture, externalTexture};
+        std::vector<std::shared_ptr<ExternalTexture>> textures = {srcTexture, externalTexture};
 
         // Another external texture with a different pixel format triggers useIsOpaqueWorkaround.
         // It doesn't have to be f16, but it can't be the usual 8888.