[clang-format]Update clang formatting settings to insert space into { }.

https://bugs.webkit.org/show_bug.cgi?id=286304
<rdar://143321464>

Reviewed by Yusuke Suzuki and Darin Adler.

Per the style guide, empty braces should contain a space:

https://www.webkit.org/code-style-guidelines/

However, `webkit-patch format` collapses the whitespace between curly braces.

We should add the parameter

`SpaceInEmptyBlock : true`

to insert whitespace into empty curly braces.

Documentation:

https://clang.llvm.org/docs/ClangFormatStyleOptions.html

Canonical link: https://commits.webkit.org/289207@main

.clang-format

@@ -99,6 +99,7 @@ SpaceAfterTemplateKeyword: false
 SpaceBeforeAssignmentOperators: true
 SpaceBeforeCpp11BracedList: true
 SpaceBeforeParens: ControlStatements
+SpaceInEmptyBlock : true
 SpaceInEmptyParentheses: false
 SpacesBeforeTrailingComments: 1
 SpacesInAngles:  false