Ignore blank lines between comments when counting newlines-after-imports (#7607)

## Summary

Given:

```python
# -*- coding: utf-8 -*-
import random

# Defaults for arguments are defined here
# args.threshold = None;


logger = logging.getLogger("FastProject")
```

We want to count the number of newlines after `import random`, to ensure
that there's _at least one_, but up to two.

Previously, we used the end range of the statement (then skipped
trivia); instead, we need to use the end of the _last comment_. This is
similar to #7556.

Closes https://github.com/astral-sh/ruff/issues/7604.

crates/ruff_python_formatter/src/statement/suite.rs

@@ -190,7 +190,12 @@ impl FormatRule<Suite, PyFormatContext<'_>> for FormatSuite {
                 // a leading comment.
                 match self.kind {
                     SuiteKind::TopLevel => {
-                        match lines_after_ignoring_trivia(preceding.end(), source) {
+                        let end = if let Some(last_trailing) = preceding_comments.trailing.last() {
+                            last_trailing.end()
+                        } else {
+                            preceding.end()
+                        };
+                        match lines_after(end, source) {
                             0..=2 => empty_line().fmt(f)?,
                             _ => match source_type {
                                 PySourceType::Stub => {