ESC docs still reference the retired standalone esc CLI instead of pulumi env

[workprentice]

The standalone esc CLI is retired (v0.26.0 was its final release; pulumi/esc is
archived and the code now lives in pulumi/pulumi). See the retirement announcement:
Say hello to pulumi env, and goodbye to the standalone esc CLI
and the migration guide at Migrating from the esc CLI.

Several ESC docs pages still instruct readers to run the retired esc CLI instead of
pulumi env:

1. content/docs/esc/providers/secrets/1password-secrets.md — presents esc open ...
   (linking to a redirect at /docs/esc-cli/) as a parallel option alongside
   pulumi env open ..., when only the latter should be documented.
2. content/docs/esc/concepts/interpolations-and-references.md — an example uses
   esc env open <environment> --lifetime 30m instead of
   pulumi env open <environment> --lifetime 30m.
3. content/docs/esc/concepts/outputs.md — a "Precedence" example uses
   esc run default/greet -- printenv GREETING instead of
   pulumi env run default/greet -- printenv GREETING; a few lines above it, the same
   file already correctly uses pulumi env run, so this is the last stale invocation.

Note: content/docs/iac/cli/commands/pulumi_env_webhook_new.md also mentions
"esc env webhook subcommands" in its generated help text, but that file is
auto-generated CLI reference content and out of scope for a docs-repo fix; the stale
phrasing originates upstream in pulumi/pulumi's CLI help text.