Update ocean-controller-two-install.md

[cobbg]

Corrected spelling error for environment variable reference in scale down old controller replicas section. $EXISITNG_NAMESPACE to $EXISTING_NAMESPACE.

Removed stray spaces in Helm install block that cause errors during execution.

This is the default pull request template. You can customize it by adding a pull_request_template.md at the root of your repo or inside the .github folder.

Jira Ticket

Include a link to your Jira Ticket
Example: JIRAISS-1234

Demo

Please add a recording of the feature/bug fix in work. if you added new routes, the recording should show the request and response for each new/changed route

Checklist:

• I have filled relevant self assessment (NodeJS, Frontend, Backend)
• I have run ESlint on my changes and fixed all warnings and errors (NodeJS & Frontend Services)
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have validated all the requirements in the Jira task were answered
• I have all neccessary approvals for the design/mini design of this task
• I have approved the API changes and granular permission patterns (documentation subtask) (For public services only)