[clang-format] Extra spaces surrounding arrow in templated member call in variable decl

https://github.com/llvm/llvm-project/issues/43196

Fixes #43196

-> is incorrectly interpreted as a TrailingReturnArrow if we've seen an auto

```
auto p = new A;
auto x = p -> foo<1>();
```

Reviewed By: curdeius

Differential Revision: https://reviews.llvm.org/D115903