fix(CocoaPods): Stop taking pure version constraints as dependencies

Second-level entries in the "PODS" section are just "pure" constraints
which should not be added as dependencies at all unless their names also
appear with resolved versions as first-level entries.

This partly reverts 18f9be2 which introduced this over-reporting by
unconditionally adding constraints as dependencies. However, that did
not surface until the test added in 4bbd26a.

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>

plugins/package-managers/cocoapods/src/funTest/assets/projects/synthetic/external-sources-expected-output.yml

@@ -28,7 +28,6 @@ project:
  - id: "Pod::AFNetworking/Reachability:3.2.1"
  - id: "Pod::AFNetworking/Security:3.2.1"
  - id: "Pod::AFNetworking/Serialization:3.2.1"
- - id: "Pod::AFNetworking/UIKit:3.2.1"
  - id: "Pod::CocoaSecurity:1.2.4"
  - id: "Pod::MLHudAlert:0.0.4-3f23fa41632f8935fed028b04335576633ec53a2"
  - id: "Pod::Ono:2.1.1"
@@ -173,34 +172,6 @@ packages:
  url: "https://github.com/AFNetworking/AFNetworking.git"
  revision: "3.2.1"
  path: ""
-- id: "Pod::AFNetworking/UIKit:3.2.1"
- purl: "pkg:cocoapods/AFNetworking%2FUIKit@3.2.1"
- declared_licenses:
- - "MIT"
- declared_licenses_processed:
- spdx_expression: "MIT"
- description: "A delightful iOS and OS X networking framework."
- homepage_url: "https://github.com/AFNetworking/AFNetworking"
- binary_artifact:
- url: ""
- hash:
- value: ""
- algorithm: ""
- source_artifact:
- url: ""
- hash:
- value: ""
- algorithm: ""
- vcs:
- type: "Git"
- url: "https://github.com/AFNetworking/AFNetworking.git"
- revision: "3.2.1"
- path: ""
- vcs_processed:
- type: "Git"
- url: "https://github.com/AFNetworking/AFNetworking.git"
- revision: "3.2.1"
- path: ""
 - id: "Pod::CocoaSecurity:1.2.4"
  purl: "pkg:cocoapods/CocoaSecurity@1.2.4"
  declared_licenses: