Ensure escape on TOML and requirements is treated as cancel.

Author: karthiknadig

src/client/pythonEnvironments/creation/provider/venvUtils.ts

@@ -151,6 +151,8 @@ export async function pickPackagesToInstall(
                                 });
                             }
                             packages.push({ installType: 'toml', source: tomlPath });
+                        } else {
+                            return MultiStepAction.Cancel;
                         }
                     } catch (ex) {
                         if (ex === MultiStepAction.Back || ex === MultiStepAction.Cancel) {
@@ -192,6 +194,8 @@ export async function pickPackagesToInstall(
                         installList.forEach((i) => {
                             packages.push({ installType: 'requirements', installItem: i });
                         });
+                    } else {
+                        return MultiStepAction.Cancel;
                     }
                 } catch (ex) {
                     if (ex === MultiStepAction.Back || ex === MultiStepAction.Cancel) {

src/test/pythonEnvironments/creation/provider/venvUtils.unit.test.ts

@@ -80,7 +80,7 @@ suite('Venv Utils test', () => {
             '[project]\nname = "spam"\nversion = "2020.0.0"\n[build-system]\nrequires = ["setuptools ~= 58.0", "cython ~= 0.29.0"]\n[project.optional-dependencies]\ntest = ["pytest"]\ndoc = ["sphinx", "furo"]',
         );
 
-        showQuickPickWithBackStub.rejects(windowApis.MultiStepAction.Cancel);
+        showQuickPickWithBackStub.resolves(undefined);
 
         await assert.isRejected(pickPackagesToInstall(workspace1));
         assert.isTrue(
@@ -215,7 +215,7 @@ suite('Venv Utils test', () => {
             return Promise.resolve([]);
         });
 
-        showQuickPickWithBackStub.rejects(windowApis.MultiStepAction.Cancel);
+        showQuickPickWithBackStub.resolves(undefined);
 
         await assert.isRejected(pickPackagesToInstall(workspace1));
         assert.isTrue(