fix: avoid double slash if glob ends with slash (#6772)
### Description
Fixes #6748
### Testing Instructions
Added unit test making sure we don't have multiple forward slashes in
the `package.json` globs.
Also tested that we no longer error if a workspace glob has a trailing
slash:
```
[0 olszewski@chriss-mbp] /tmp/trailing-slash $ cat pnpm-workspace.yaml
packages:
- "apps/*"
- "packages/*"
- ci/
# before changes in PR
[0 olszewski@chriss-mbp] /tmp/trailing-slash $ turbo_dev info
Turbo error: discovery failed: bad pattern /private/tmp/trailing-slash/ci//package.json: malformed glob expression: adjacent component bounda
ries `/` or `**`
# after PR changes
[0 olszewski@chriss-mbp] /tmp/trailing-slash $ turbo_dev info
You are logged in but not linked
6 packages found in workspace
- @repo/eslint-config packages/eslint-config
- @repo/typescript-config packages/typescript-config
- @repo/ui packages/ui
- ci ci
- docs apps/docs
- web apps/web
```
Closes TURBO-1896
Co-authored-by: Chris Olszewski <Chris Olszewski>
