`webserver.instance_name` shows markup text in `<title>` tag

[IAL32]

Apache Airflow version

2.5.0

What happened

#20888 enables the use of markup to style the webserver.instance_name.
However, if the instance name has HTML code, this will also be reflected in the <title> tag, as shown in the screenshot below.

This is not a pretty behaviour.

What you think should happen instead

Ideally, if webserver. instance_name_has_markup = True, then the text inside the <title> should be stripped of HTML code.

For example:

• Set webserver.instance_name to some text with markup, like <b style="color: red">title</b>
• Set webserver.Instance_name_has_markup to true

This is how the <title> tag should look like:

<title>DAGs - title</title>

Instead of:

<title>DAGs - &lt;b style=&#34;color: red&#34;&gt;title&lt;b&gt;</title>

How to reproduce

• Airflow version 2.3+, which is when this change has been introduced
• Set webserver.instance_name to some text with markup, like <b style="color: red">title</b>
• Set webserver.Instance_name_has_markup to true

Operating System

Doesn't matter

Versions of Apache Airflow Providers

No response

Deployment

Other

Deployment details

No response

Anything else

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

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[amoghrajesh]

@IAL32 are you actively working on this? I see the PR was not merged. I can take it forward.

[potiuk]

Assigned you @amoghrajesh

[IAL32]

@amoghrajesh hello there! I mean, the PR #28894 is ready, so there is not much to bring forward unfortunately 😅 feel free to pitch in, though!