Remove spaces from import statements (#7859)

**Summary** Remove spaces from import statements such as 

```python
import tqdm .  tqdm
from tqdm .    auto import tqdm
```

See also #7760 for a better solution.

**Test Plan** New fixtures

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/import.py

@@ -9,6 +9,8 @@ import foo\
 from foo\
     .bar import baz
 
+import tqdm  . tqdm
+
 # At the top-level, force one empty line after an import, but allow up to two empty
 # lines.
 import os

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/import_from.py

@@ -35,3 +35,5 @@ from a import \
     (  # comment
     bar,
 )
+
+from tqdm .  auto import tqdm

crates/ruff_python_formatter/src/other/identifier.rs

@@ -1,5 +1,6 @@
 use ruff_formatter::{FormatOwnedWithRule, FormatRefWithRule};
 use ruff_python_ast::Identifier;
+use ruff_python_trivia::is_python_whitespace;
 use ruff_text_size::Ranged;
 
 use crate::prelude::*;
@@ -31,6 +32,7 @@ impl<'ast> IntoFormat<PyFormatContext<'ast>> for Identifier {
 /// A formatter for a dot-delimited identifier, as seen in import statements:
 /// ```python
 /// import foo.bar
+/// from tqdm   . auto import tqdm
 /// ```
 ///
 /// Dot-delimited identifiers can contain newlines via continuations (backslashes) after the
@@ -54,14 +56,25 @@ impl<'a> DotDelimitedIdentifier<'a> {
 
 impl Format<PyFormatContext<'_>> for DotDelimitedIdentifier<'_> {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
-        // An import identifier can contain newlines by inserting continuations (backslashes) after
+        // An import identifier can contain whitespace around the dots:
+        // ```python
+        // import importlib   .   metadata
+        // ```
+        // It can also contain newlines by inserting continuations (backslashes) after
         // a dot-delimited segment, as in:
         // ```python
         // import foo\
-        //    .bar
+        //     .bar
         // ```
-        if memchr::memchr(b'\\', f.context().source()[self.0.range()].as_bytes()).is_some() {
-            text(self.0.as_str(), Some(self.0.start())).fmt(f)
+        if f.context().source()[self.0.range()]
+            .chars()
+            .any(|c| is_python_whitespace(c) || matches!(c, '\n' | '\r' | '\\'))
+        {
+            let no_whitespace: String = f.context().source()[self.0.range()]
+                .chars()
+                .filter(|c| !is_python_whitespace(*c) && !matches!(c, '\n' | '\r' | '\\'))
+                .collect();
+            text(&no_whitespace, Some(self.0.start())).fmt(f)
         } else {
             source_text_slice(self.0.range()).fmt(f)
         }

crates/ruff_python_formatter/tests/snapshots/format@statement__import.py.snap

@@ -15,6 +15,8 @@ import foo\
 from foo\
     .bar import baz
 
+import tqdm  . tqdm
+
 # At the top-level, force one empty line after an import, but allow up to two empty
 # lines.
 import os
@@ -110,6 +112,8 @@ import foo.bar
 
 from foo.bar import baz
 
+import tqdm.tqdm
+
 # At the top-level, force one empty line after an import, but allow up to two empty
 # lines.
 import os

crates/ruff_python_formatter/tests/snapshots/format@statement__import_from.py.snap

@@ -41,6 +41,8 @@ from a import \
     (  # comment
     bar,
 )
+
+from tqdm .  auto import tqdm
 ```
 
 ## Output
@@ -115,6 +117,8 @@ from a import (
 from a import (  # comment
     bar,
 )
+
+from tqdm.auto import tqdm
 ```