[clang-format] Fix anonymous reference parameter with default value (#86254)

When enabling alignment of consecutive declarations and reference right
alignment, the needed space between `& ` and ` = ` is removed in the
following use case.

Problem (does not compile)
```
int    a(const Test    &= Test());
double b();
```

Expected:
```
int    a(const Test & = Test());
double b();
```

Test command:

```
echo "int    a(const Test& = Test()); double b();" | clang-format -style="{AlignConsecutiveDeclarations: true, ReferenceAlignment: Right}"
```