[core] Create glyph manager at renderer construction time

Avoid unnecessary glyph manager presence check in `Renderer::Impl::()`.

test/tile/vector_tile.test.cpp

@@ -28,7 +28,7 @@ public:
     style::Style style { fileSource, 1 };
     AnnotationManager annotationManager { style };
     ImageManager imageManager;
-    GlyphManager glyphManager { fileSource };
+    GlyphManager glyphManager;
     Tileset tileset { { "https://example.com" }, { 0, 22 }, "none" };
 
     TileParameters tileParameters {
@@ -103,4 +103,4 @@ TEST(VectorTileData, ParseResults) {
     ASSERT_EQ(properties.at("disputed"), *feature->getValue("disputed"));
 
     ASSERT_EQ(feature->getValue("invalid"), nullopt);
-}
+}