Remove unused isDev constant from CLI version module (#33858)

The `isDev` export in `packages/cli/src/wiring/version.ts` was never
imported anywhere. Remove it to reduce dead code.


Made-with: Cursor

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/remove-unused-isdev-constant.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Removed the unused `isDev` export from the internal version module.

packages/cli/src/wiring/version.ts

@@ -26,4 +26,3 @@ export function findVersion() {
 }
 
 export const version = findVersion();
-export const isDev = fs.pathExistsSync(ownPaths.resolve('src'));