[typescript-angular] Prevent syntax error when using isDateTime=true

Created by: HexagonSun

Fixes a bug where the the append method's closing brace was not generated when using code-generation option isDateTime=true.

Fixes #11267 (closed).

Additional information

In addition to the minimal change that would be needed to fix the issue, I've modified the template and put the statement on a single line. I do not see a good reason for the method parameters to be split across two lines _with the closing parenthesis being on the same line as the second parameter. I think this might have caused the bug in the first place, since it's not clearly visible which closing parenthesis belongs to which opening one.
Personally, if a link-break is desired, I'd write it like this, with every parameter on a separate line:

httpParams = httpParams.append(
    key,
    (value as Date).toISOString().substr(0, 10)
);

But I don't really think that line breaks improve the readability, so I removed them altogether. This is the reason that the generated samples changed.

To verify

To verify:

1. run the generator using isDateTime=true:

   ./bin/generate-samples.sh ./bin/configs/typescript-angular-v13-provided-in-root.yaml -- --additional-properties=isDateTime=true

2. Verify that the generated *.service file is syntactically correct, with the parenthesis properly balanced:

   …
   httpParams = httpParams.append(key, (value as Date).toISOString());
   …

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh

  Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master (5.3.0), 6.0.x
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.