feat: Allow user to change metadata when instantiating from hash

[CharliePops]

Fixes #457

Proposed Changes

Allow the user to select a different metadata when instantiating from hash or re-instantiating, associating the selected metadata to the new instance being created.

https://github.com/paritytech/contracts-ui/assets/163580/627a2b40-a452-41cc-9279-885a95100f82

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[cla-bot-2021[bot]]

User @CharliePops, please sign the CLA here.

[statictype]

thank you for submitting this @CharliePops! will review it asap.

[statictype]

please see my issue comment. the current behaviour where the metadata is revered to the original one is correct

[CharliePops]

No problem, I will update it.