fix(cache/redis): use connectionAwareSerialize in RedisStore::putMany()

[superbiche]

Cache RedisStore::putMany() should not serialize values if the connection already uses serialization.

This prevents a bug with the following setup:

• Using Redis cache driver
• Using phpredis client
• Configuring phpredis to use serialization - eg "serializer" => Redis::SERIALIZER_IGBINARY

When using Cache::flexible(), the value returned is correct only the first time. Subsequent calls return a PHP serialized value:

> Cache::flexible('test:flex', [now()->addHours(12), now()->addHours(24)], fn () => ["test" => "ok"] )
= [
    "test" => "ok",
  ]

> Cache::flexible('test:flex', [now()->addHours(12), now()->addHours(24)], fn () => ["test" => "ok"])
= "a:1:{s:4:"test";s:2:"ok";}"

This is caused by RedisStore::putMany() method, which - contrarily to other methods in this class - doesn't use RedisStore::connectionAwareSerialize.
In the meantime, RedisStore::many() method uses RedisStore::connectionAwareUnserialize(), so it doesn't unserialize the value that is returned.

This PR fixes this inconsistent behavior by changing RedisStore::putMany() so it uses RedisStore::connectionAwareSerialize.

The result is what one should expect:

> Cache::flexible('test:flex', [now()->addHours(12), now()->addHours(24)], fn () => ["test" => "ok"] )
= [
    "test" => "ok",
  ]

> Cache::flexible('test:flex', [now()->addHours(12), now()->addHours(24)], fn () => ["test" => "ok"] )
= [
    "test" => "ok",
  ]