fix: force a timezone if one not provided by deeplinks

[langswei]

Spacecat and possibly other sources publish deeplinks to the dashboard. A bug was identified where a missing timezone turns into an empty string through certain navigation after the deeplink, which broke the run-query. These commits are meant to always populate a missing timezone with the users timezone, including in the initial run-query call.

Test URLs:

• Before: https://data.aem.live/rum-dashboard?url=www.aem.live&domainkey=d77c830d-3ec9-4611-8b86-256346fa7659&startdate=2024-01-24&enddate=2024-02-23. Notice in Developer Tools there is no timezone param in the run-query call. Click Search and it will fail. Notice in Developer Tools timezone exists with an empty value.
• After: https://deeplink-timezone-fix--franklin-dashboard--adobe.hlx.live/rum-dashboard?url=www.aem.live&domainkey=d77c830d-3ec9-4611-8b86-256346fa7659&startdate=2024-01-24&enddate=2024-02-23. Notice the timezone field in left filter is populated. Notice in Developer Tools there is a timezone param in the run-query call. Click various links on the page and the timezone is retained and run-query calls do not break.

[aem-code-sync[bot]]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed. In case there are problems, just click a checkbox below to rerun the respective action.

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Commits

* [39065c9](https://github.com/adobe/franklin-dashboard/pull/85/commits/39065c92385a0a16ba95a070db4b54561190ecfc) :white_check_mark: (latest) * [af5aebe](https://github.com/adobe/franklin-dashboard/pull/85/commits/af5aebedb57f69d88935247b6e7357be996410bc) :white_check_mark:

[aem-code-sync[bot]]

Page	Scores	Audits	Google
/rum-dashboard?url=www.aem.live&domainkey=d77c830d-3ec9-4611-8b86-256346fa7659&s tartdate=2024-01-24&enddate=2024-02-23.		Lighthouse returned error: NO_FCP. The page did not paint any content. Please ensure you keep the browser window in the foreground during the load and try again. (NO_FCP)