:bug: Drop UTC offset for local time used in tasks table

[rszwajko]

The API provides date/time in UTC. For user convenience we display it in the browser time zone. Before this PR, UTC offset for the local time zone was included.

The format used is a subset of ISO 8601 which allows for predictable sorting in the table. Format string: "YYYY-MM-DD HH:mm:ss". Example date: "2024-07-03 13:21:44".

Part-of: #1969

[rszwajko]

Before

After

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 42.32%. Comparing base (b654645) to head (d724674). Report is 185 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1994 +/- ## ========================================== + Coverage 39.20% 42.32% +3.12% ========================================== Files 146 170 +24 Lines 4857 5434 +577 Branches 1164 1305 +141 ========================================== + Hits 1904 2300 +396 - Misses 2939 3118 +179 - Partials 14 16 +2 ``` | [Flag](https://app.codecov.io/gh/konveyor/tackle2-ui/pull/1994/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=konveyor) | Coverage Δ | | |---|---|---| | [client](https://app.codecov.io/gh/konveyor/tackle2-ui/pull/1994/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=konveyor) | `42.32% <ø> (+3.12%)` | :arrow_up: | | [server](https://app.codecov.io/gh/konveyor/tackle2-ui/pull/1994/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=konveyor) | `?` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=konveyor#carryforward-flags-in-the-pull-request-comment) to find out more.

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