Add allow-unused-imports setting for unused-import rule (F401) (#13601)

## Summary
Resolves https://github.com/astral-sh/ruff/issues/9962 by allowing a
configuration setting `allowed-unused-imports`

TODO:
- [x] Figure out the correct name and place for the setting; currently,
I have added it top level.
- [x] The comparison is pretty naive. I tried using `glob::Pattern` but
couldn't get it to work in the configuration.
- [x] Add tests
- [x] Update documentations

## Test Plan

`cargo test`

crates/ruff_workspace/src/configuration.rs

@@ -626,6 +626,7 @@ pub struct LintConfiguration {
     pub logger_objects: Option<Vec<String>>,
     pub task_tags: Option<Vec<String>>,
     pub typing_modules: Option<Vec<String>>,
+    pub allowed_unused_imports: Option<Vec<String>>,
 
     // Plugins
     pub flake8_annotations: Option<Flake8AnnotationsOptions>,
@@ -738,6 +739,7 @@ impl LintConfiguration {
             task_tags: options.common.task_tags,
             logger_objects: options.common.logger_objects,
             typing_modules: options.common.typing_modules,
+            allowed_unused_imports: options.common.allowed_unused_imports,
             // Plugins
             flake8_annotations: options.common.flake8_annotations,
             flake8_bandit: options.common.flake8_bandit,
@@ -1106,6 +1108,9 @@ impl LintConfiguration {
                 .or(config.explicit_preview_rules),
             task_tags: self.task_tags.or(config.task_tags),
             typing_modules: self.typing_modules.or(config.typing_modules),
+            allowed_unused_imports: self
+                .allowed_unused_imports
+                .or(config.allowed_unused_imports),
             // Plugins
             flake8_annotations: self.flake8_annotations.combine(config.flake8_annotations),
             flake8_bandit: self.flake8_bandit.combine(config.flake8_bandit),
@@ -1327,6 +1332,7 @@ fn warn_about_deprecated_top_level_lint_options(
         explicit_preview_rules,
         task_tags,
         typing_modules,
+        allowed_unused_imports,
         unfixable,
         flake8_annotations,
         flake8_bandit,
@@ -1425,6 +1431,9 @@ fn warn_about_deprecated_top_level_lint_options(
     if typing_modules.is_some() {
         used_options.push("typing-modules");
     }
+    if allowed_unused_imports.is_some() {
+        used_options.push("allowed-unused-imports");
+    }
 
     if unfixable.is_some() {
         used_options.push("unfixable");

crates/ruff_workspace/src/options.rs

@@ -796,6 +796,16 @@ pub struct LintCommonOptions {
     )]
     pub typing_modules: Option<Vec<String>>,
 
+    /// A list of modules which is allowed even thought they are not used
+    /// in the code.
+    ///
+    /// This is useful when a module has a side effect when imported.
+    #[option(
+        default = r#"[]"#,
+        value_type = "list[str]",
+        example = r#"allowed-unused-imports = ["hvplot.pandas"]"#
+    )]
+    pub allowed_unused_imports: Option<Vec<String>>,
     /// A list of rule codes or prefixes to consider non-fixable.
     #[option(
         default = "[]",
@@ -2812,12 +2822,28 @@ pub struct PyflakesOptions {
         example = "extend-generics = [\"django.db.models.ForeignKey\"]"
     )]
     pub extend_generics: Option<Vec<String>>,
+
+    /// A list of modules to ignore when considering unused imports.
+    ///
+    /// Used to prevent violations for specific modules that are known to have side effects on
+    /// import (e.g., `hvplot.pandas`).
+    ///
+    /// Modules in this list are expected to be fully-qualified names (e.g., `hvplot.pandas`). Any
+    /// submodule of a given module will also be ignored (e.g., given `hvplot`, `hvplot.pandas`
+    /// will also be ignored).
+    #[option(
+        default = r#"[]"#,
+        value_type = "list[str]",
+        example = r#"allowed-unused-imports = ["hvplot.pandas"]"#
+    )]
+    pub allowed_unused_imports: Option<Vec<String>>,
 }
 
 impl PyflakesOptions {
     pub fn into_settings(self) -> pyflakes::settings::Settings {
         pyflakes::settings::Settings {
             extend_generics: self.extend_generics.unwrap_or_default(),
+            allowed_unused_imports: self.allowed_unused_imports.unwrap_or_default(),
         }
     }
 }