Cleanup members table layout and buttons

What does this MR do and why?

Related to #356712 (closed)

The members table is getting cramped with all of the fields and it causes horizontal scroll on some of mid-width screen sizes. This MR moves the User created, Access granted, and Last activity fields into one Activity column. It also updates the action buttons to be more consistent and take up less space.

Screenshots or screen recordings

Group

Members

Before	After

Before	After

Groups

Before	After

Before	After

Invited

Before	After

Before	After

Access requests

Before	After

Before	After

Project

Members

Before	After

Before	After

Groups

Before	After

Before	After

Invited

Before	After

Before	After

Access requests

Before	After

Before	After

How to set up and validate locally

Group

Create a group

How to add a group

1. Navigate to Group -> Members
2. Click the Invite a group button
3. Choose a group

How to add an invited member

1. Navigate to Group -> Members
2. Click Invite members
3. In the GitLab member or Email address enter an email that a user does not already own
4. Click Invite "example@test.com" by email

How to request access to a group

1. Log in (or impersonate) a user that doesn't already have access to the group
2. Navigate to the group overview
3. Click Request access located to the right of the group name

Project

Create a project

How to add a group

1. Navigate to Project -> Members
2. Click the Invite a group button
3. Choose a group

How to add an invited member

1. Navigate to Project -> Members
2. Click Invite members
3. In the GitLab member or Email address enter an email that a user does not already own
4. Click Invite "example@test.com" by email

How to request access to a project

1. Log in (or impersonate) a user that doesn't already have access to the project
2. Navigate to the project overview
3. Click Request access located to the right of the project name

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.