Add a getter for providers to the ChainUserProvider class
merged branch elnur/chain-user-provider-getter (PR #7077)

This PR was merged into the master branch.

Discussion
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[2.3] [Security] Add a getter for providers to the ChainUserProvider class

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes

I've got a use case where I need to check if any of the chained user providers implement a particular interface. This getter would really help with that.

Commits
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0a82d73 Add a getter for providers to the ChainUserProvider class