Update "WordPress Beta" steps installPlugin and login

[bph]

Fixed #124 to use shorthand for plugins and login steps

[github-actions]

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Test this pull request with WordPress Playground.

[bph]

For now, it crashed WASM due to CORS issues. Same problem as this issue:
WordPress/wordpress-playground#2138

[bph]

Tested it again today and it ran into three error messages, (1) and (2) are new, (3) is the crash error message already encountered.

1

[04-Mar-2025 18:33:55 UTC] PHP Notice: Function _load_textdomain_just_in_time was called incorrectly. Translation loading for the debug-bar domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init action or later. Please see Debugging in WordPress for more information. (This message was added in version 6.7.0.) in /wordpress/wp-includes/functions.php on line 135

2

[04-Mar-2025 18:33:56 UTC] PHP Notice: Function _load_textdomain_just_in_time was called incorrectly. Translation loading for the health-check domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init action or later. Please see Debugging in WordPress for more information. (This message was added in version 6.7.0.) in /wordpress/wp-includes/functions.php on line 135

3

[04-Mar-2025 18:34:39 UTC] WASM Crash Fatal: memory access out of bounds Error: memory access out of bounds
at #handleRequest (https://playground.wordpress.net/worker-thread-d0d81a62.js:53:5901)
at async PHP.run (https://playground.wordpress.net/worker-thread-d0d81a62.js:53:1789)
at async PlaygroundWorkerEndpoint.run (https://playground.wordpress.net/worker-thread-d0d81a62.js:4:9449)
[04-Mar-2025 18:34:39 UTC] JavaScript Error: memory access out of bounds
Error: memory access out of bounds
at #handleRequest (https://playground.wordpress.net/worker-thread-d0d81a62.js:53:5901)
at async PHP.run (https://playground.wordpress.net/worker-thread-d0d81a62.js:53:1789)
at async PlaygroundWorkerEndpoint.run (https://playground.wordpress.net/worker-thread-d0d81a62.js:4:9449)