docs: mention PSS in changeover procedure and replace Replicated Security with Interchain Security (backport #1981)

[mergify]

Description

Closes: #1971

Note that not all "replicated security" references were changed to "interchain security" when "replicated security" is used to refer to the specific protocol. For example, in the PSS ADR we refer to what the replicated security protocol was doing and hence it doesn't make sense to replace "replicated security" with "interchain security."

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• included the correct docs: prefix in the PR title
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Summary by CodeRabbit

• Documentation
  • Updated terminology from "Replicated Security" to "Interchain Security" across various documents.
  • Clarified validator set sharing between provider and consumer chains.
  • Refined changeover procedures for transitioning standalone chains to Interchain Security.
  • Updated reward distribution documentation to reflect new security terms.
  • Improved clarity on validator requirements and node setup for Interchain Security.

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This is an automatic backport of pull request #1981 done by [Mergify](https://mergify.com).