Fix repositories array becoming a JSON object after path-type dedup

[kayw-geek]

Fixes #113.

RepositoryPathComposerJsonDecorator::processRemoveDuplicates() used unset() without reindexing, leaving non-sequential integer keys in the repositories array. Nette\Utils\Json::encode() then serializes that as a JSON object instead of an array — valid Composer-wise, but a noisy diff and breaks tooling that assumes a list.

Fix:

• Wrap the final assignment in array_values(...) to reindex.
• Add continue; after unset() so a discarded URL isn't re-pushed onto $paths.
• Update the existing decorator test fixture to assert sequential keys (was asserting the buggy 0, 1, 3).