sweep: Add UI for setting Sweep API token in system keychain (#43502)

Closes #ISSUE

Release Notes:

- N/A *or* Added/Fixed/Improved ...

Cargo.lock

@@ -5299,6 +5299,7 @@ dependencies = [
  "indoc",
  "language",
  "lsp",
+ "menu",
  "paths",
  "project",
  "regex",
@@ -5308,6 +5309,7 @@ dependencies = [
  "telemetry",
  "theme",
  "ui",
+ "ui_input",
  "util",
  "workspace",
  "zed_actions",
@@ -21678,6 +21680,7 @@ dependencies = [
  "collections",
  "command_palette_hooks",
  "copilot",
+ "credentials_provider",
  "ctor",
  "db",
  "edit_prediction",