[clang-format] Change LLVM style to BreakAfterAttributes == ABS_Leave (#70360)

This patch addresses some examples of bad formatting in Clang. The following commit contains only changes suggested by clang-format: https://github.com/llvm/llvm-project/pull/70349/commits/21689b56d1fc1db0b2263e8049ff656d3757ad36.
I believe it's a net negative on readability, with a couple of particularly bad cases. Highlights:
```diff
-    [[clang::preferred_type(bool)]]
-    mutable unsigned CachedLocalOrUnnamed : 1;
+    [[clang::preferred_type(bool)]] mutable unsigned CachedLocalOrUnnamed : 1;
```
```diff
-    [[clang::preferred_type(TypeDependence)]]
-    unsigned Dependence : llvm::BitWidth<TypeDependence>;
+    [[clang::preferred_type(TypeDependence)]] unsigned Dependence
+        : llvm::BitWidth<TypeDependence>;
```
```diff
-    [[clang::preferred_type(ExceptionSpecificationType)]]
-    unsigned ExceptionSpecType : 4;
+    [[clang::preferred_type(
+        ExceptionSpecificationType)]] unsigned ExceptionSpecType : 4;
```
Style guides doesn't appear to have an opinion on this matter.