fix: Change "Single Account" to "Single Project" in button text (#200327)

## Summary

This pull request resolves
[#198879](https://github.com/elastic/kibana/issues/198879), where
"Single Account" was incorrectly displayed in the GCP integration
screen. The text has been updated to "Single Project" to align with GCP
terminology. Additionally, the paragraph above this text was updated to
ensure consistency across the UI.

## Motivation

Aligning the GCP integration screen with GCP’s correct terminology by
replacing "Single Account" with "Single Project" ensures clarity and
consistency across the UI.

## Screenshots:
**Before**: interface showing "Single Account"

<img width="858" alt="Screenshot 2024-11-18 at 1 29 18 PM"
src="https://github.com/user-attachments/assets/c03cb5f0-8e30-4e90-852d-aa2e91d6918d">

**After**: updated interface showing "Single Project"

<img width="782" alt="Screenshot 2024-11-18 at 1 29 57 PM"
src="https://github.com/user-attachments/assets/2d1b3e09-8da8-401a-b711-34934c31a1b2">


### Checklist

Check the PR satisfies following conditions. 

Reviewers should verify this PR satisfies this list as well.

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
~~[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials~~
- [ ] ~~[Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios~~
- [ ] ~~If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)~~
- [ ] ~~This was checked for breaking HTTP API changes, and any breaking
changes have been approved by the breaking-change committee. The
`release_note:breaking` label should be applied in these situations.~~
- [ ] ~~[Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed~~
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_node:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: Maxim Kholod <maxim.kholod@elastic.co>

x-pack/plugins/cloud_security_posture/public/components/fleet_extensions/policy_template_form.tsx

@@ -148,7 +148,7 @@ const getGcpAccountTypeOptions = (isGcpOrgDisabled: boolean): CspRadioGroupProps
   {
     id: GCP_SINGLE_ACCOUNT,
     label: i18n.translate('xpack.csp.fleetIntegration.gcpAccountType.gcpSingleAccountLabel', {
-      defaultMessage: 'Single Account',
+      defaultMessage: 'Single Project',
     }),
     testId: 'gcpSingleAccountTestId',
   },
@@ -377,7 +377,7 @@ const GcpAccountTypeSelect = ({
       <EuiText color="subdued" size="s">
         <FormattedMessage
           id="xpack.csp.fleetIntegration.gcpAccountTypeDescriptionLabel"
-          defaultMessage="Select between single account or organization, and then fill in the name and description to help identify this integration."
+          defaultMessage="Select between single project or organization, and then fill in the name and description to help identify this integration."
         />
       </EuiText>
       <EuiSpacer size="l" />