Remove default indent from .editorconfig (#49136)

Prior to 3a3e5f6, there was no default indent configured in
`.editorconfig`. This changed to 4 spaces when we configured an explicit
indent of 2 for Gradle files. However, this change meant that YAML files
then had 4-space indents, which is valid, but the repo's YAML files
typically use 2-space indents.

Remove the default indent again, and instead explicitly set an indent size
for a variety of file types.

.editorconfig

@@ -7,10 +7,27 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 indent_style = space
+
+[*.gradle]
+indent_size = 2
+
+[*.groovy]
 indent_size = 4
 
-[*.bat]
+[*.java]
+indent_size = 4
+
+[*.json]
 indent_size = 2
 
-[*.gradle]
+[*.py]
 indent_size = 2
+
+[*.sh]
+indent_size = 2
+
+[*.{yml,yaml}]
+indent_size = 2
+
+[*.{xsd,xml}]
+indent_size = 4