Users should only be able to push from the current folder

[lucasfcosta]

Summary

When using push, the agent will use the cwd as the path from which it will read a configuration file.

That behaviour is problematic because if the user is using the agent to push journeys from a different target folder, they'll read the incorrect configuration file (or none), not the configuration in the target folder.

Therefore, we have decided that we will only allow pushing from the current working directory. That eliminates the confusion people could have if they were pushing multiple different folders (wondering which config would be used for each).

How to reproduce

1. Create a Synthetics project using the init command
2. Update config file in the new folder created by init, changing its schedule

    import type { SyntheticsConfig } from '@elastic/synthetics';
   
    export default env => {
      const config: SyntheticsConfig = {
        params: {
          url: 'https://elastic.github.io/synthetics-demo/',
        },
        playwrightOptions: {
          ignoreHTTPSErrors: false,
        },
        /**
         * Configure global monitor settings
         */
        monitor: {
          schedule: 25,
          locations: ["brazil"],
        },
      };
      if (env !== 'development') {
        /**
         * Override configuration specific to environment
         * Ex: config.params.url = ""
         */
      }
      return config;
    };

3. Copy this config file to /tmp and change the schedule's value to something else, like 50, for example.
4. Navigate (cd) into /tmp and run the push command from there, specifying the other directory (the one you created with init)
5. You'll see the monitors get created with the schedule from /tmp, not the one within the target folder's config file.

The desired behaviour is to always use cwd and not allow a path to be passed, as we discussed on Slack.

[lucasfcosta]

I have repurposed this issue to reflect our discussions on Slack.

[shahzad31]

Push command works without following error now

errors: [
    {
      detail: [Error],
      id: '',
      location: null,
      notes: [Array],
      pluginName: 'esbuild-multiasset-plugin',
      text: "ENOENT: no such file or directory, open '/Users/shahzad-16/elastic/synthetics/examples/todos/file:/Users/shahzad-16/elastic/synthetics/examples/todos/basic.journey.ts'"
    }
  ],

[lucasfcosta]

@shahzad31 that's a different error. It's fixed by the PR #521. Can you please make sure both the target package you're pushing and this PR are tested with the latest versions?