config(inline-completion): change supplemental context configuration to always use repomap (aws#6205)

## Problem
Remove client side A/B experiment (control, treatment1, treatment2),
move it to service side and always assume treatment1

## Solution


---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).

License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: Will-ShaoHua

packages/amazonq/test/unit/codewhisperer/util/crossFileContextUtil.test.ts

@@ -96,7 +96,7 @@ describe('crossFileContextUtil', function () {
             assert.strictEqual(actual.supplementalContextItems[3].content.split('\n').length, 50)
         })
 
-        it('for t2 group, should return global bm25 context and no repomap', async function () {
+        it.skip('for t2 group, should return global bm25 context and no repomap', async function () {
             await toTextEditor(aStringWithLineCount(200), 'CrossFile.java', tempFolder, { preview: false })
             const myCurrentEditor = await toTextEditor('', 'TargetFile.java', tempFolder, {
                 preview: false,

packages/core/src/codewhisperer/util/supplementalContext/crossFileContextUtil.ts

@@ -284,14 +284,8 @@ function getSupplementalContextConfig(languageId: vscode.TextDocument['languageI
 
     const group = FeatureConfigProvider.instance.getProjectContextGroup()
     switch (group) {
-        case 'control':
-            return 'opentabs'
-
-        case 't1':
+        default:
             return 'codemap'
-
-        case 't2':
-            return 'bm25'
     }
 }