Obsolete ParameterResource.Value in favor of GetValueAsync and direct usage

[davidfowl]

Following the changes implemented in PRs #10354, #10359, and #10361, the usage of ParameterResource.Value should be considered obsolete. Instead, consumers should use GetValueAsync or access the ParameterResource directly (e.g., when used in environment variables).

Action Items:

• Mark ParameterResource.Value as obsolete in the codebase.
• Update documentation and code comments to recommend using GetValueAsync or the ParameterResource directly.
• Audit internal usage and samples to ensure the new guidance is followed.

References:

• PR #10354
• PR #10359
• PR #10361

[davidfowl]

@mitchdenny I'm not sure if we can get this over the finish line but we need to deprecate .Value.

[mitchdenny]

@davidfowl I am not sure we can get this one in either. It is pretty risky to merge. I think we would be better off carrying .Value as is for 9.4 and deprecate in 9.5.