Handle circleci command being missing in chrome install

[willzoltan]

This allows usage of the Chrome install script in Dockerfiles where circleci is not installed. Note that none of the other install scripts reply on circleci. This was working until this PR last week

Example Dockerfile snippet:

FROM cimg/ruby:3.3.6-browsers
...
# Install Chrome tools
# Parameters taken from the source code of the ORB and https://circleci.com/developer/orbs/orb/circleci/browser-tools#commands-install-chromedriver
ENV ORB_PARAM_CHANNEL=stable
ENV ORB_PARAM_CHROME_VERSION=latest
ENV ORB_PARAM_REPLACE_EXISTING=false
RUN curl -sSL "https://raw.githubusercontent.com/CircleCI-Public/browser-tools-orb/main/src/scripts/install-chrome.sh" | bash

Without this change, line 5:

PROCESSED_CHROME_VERSION=$(circleci env subst "$ORB_PARAM_CHROME_VERSION")

Fails with circleci: command not found and just sets PROCESSED_CHROME_VERSION to be empty

Before

#12 [ 7/11] RUN curl -sSL "https://raw.githubusercontent.com/CircleCI-Public/browser-tools-orb/main/src/scripts/install-chrome.sh" | bash
#12 0.070 + curl -sSL https://raw.githubusercontent.com/CircleCI-Public/browser-tools-orb/main/src/scripts/install-chrome.sh
#12 0.071 + bash
#12 0.271 bash: line 5: circleci: command not found
#12 0.278 Google Chrome is not currently installed; installing it
#12 0.283 Preparing Chrome installation for Debian-based systems
#12 0.398 Hit:1 https://download.docker.com/linux/ubuntu focal InRelease
#12 0.480 Hit:2 http://security.ubuntu.com/ubuntu focal-security InRelease
#12 0.520 Hit:3 http://archive.ubuntu.com/ubuntu focal InRelease
#12 0.600 Hit:4 http://archive.ubuntu.com/ubuntu focal-updates InRelease
#12 0.680 Hit:5 http://archive.ubuntu.com/ubuntu focal-backports InRelease
#12 0.877 Reading package lists...
#12 1.900 https://dl.google.com/linux/chrome/deb/pool/main/g/google-chrome-stable/google-chrome-stable_latest-1_amd64.deb:
#12 1.900 2024-12-09 02:36:04 ERROR 404: Not Found.
#12 1.902 bash: line 157: -2: substring expression < 0
#12 1.903 bash: line 160: google-chrome-stable: command not found
#12 1.905 bash: line 162: google-chrome-stable: command not found
#12 1.907 Google Chrome v (stable) failed to install.

After

#12 [ 7/11] RUN curl -sSL "https://raw.githubusercontent.com/CircleCI-Public/browser-tools-orb/978e55bfbabc3e9e9368f08dcc2f0410f0c53916/src/scripts/install-chrome.sh" | bash
#12 0.070 + curl -sSL https://raw.githubusercontent.com/CircleCI-Public/browser-tools-orb/978e55bfbabc3e9e9368f08dcc2f0410f0c53916/src/scripts/install-chrome.sh
#12 0.071 + bash
#12 0.223 CircleCI CLI is not installed. Relying on the environment variable ORB_PARAM_CHROME_VERSION to be set manually.
#12 0.231 Google Chrome is not currently installed; installing it
#12 0.235 Preparing Chrome installation for Debian-based systems
#12 0.304 Warning: apt-key output should not be parsed (stdout is not a terminal)
#12 0.541 OK
#12 0.551 Installing Chrome for AMD64

Checklist

• All new jobs, commands, executors, parameters have descriptions
• Examples have been added for any significant new features
• README has been updated, if necessary

Motivation, issues

Recent PR breaks our entire CircleCI pipeline

Description

• add a case to the definition of PROCESSED_CHROME_VERSION env var when circleci is missing so that the ORB_PARAM_CHROME_VERSION env var is used. Use "latest" as backup