[FIX] Issues on selecting users when importing CSV

[guijun13]

Proposed changes (including videos or screenshots)

• Fix users selecting by fixing their _id
• Add condition to disable 'Start importing' button if usersCount, channelsCount and messageCount equals 0, or if messageCount is alone
• Remove disabled={usersCount === 0} on user Tab

Steps to test or reproduce

For user selection error fix:

1. Create a CSV file (e.g. users.csv) with the following content:

bradley.hilton,bradley.hilton@example.com,Bradley Hilton
billy.bob, billy.bob@example.com, Billy Bob Jr.
graywolf336,graywolf336@example.com,GrayWolf336

2. Create a ZIP file containing only the CSV file you created in the previous step;

3. Go to Administration > Import > Import New File, then choose CSV as the Import Type and upload the ZIP file from your computer;

4. Click on Import. Expected behavior: 3 users should be displayed with all the info given in the CSV file.

5. Click on Start Importing. Expected behavior: all 3 users should be successfully imported with their corresponding real names (what can be checked in Administration > Users);

6. Delete the 3 users and repeat this process using a CSV with a single user. No error should be displayed in the whole process.

For disabled 'Start Importing' button:

1. Repeat steps 1 to 4 on the previous task.
2. Unselect all 3 users. Expected behavior: the 'Start Importing' button should be unable to click. Can also test with channels.
3. If the import .zip file contains messages, 'Start Importing' button should only be disabled when there were not any user or channel import in the same import file.

For removed disabled={usersCount === 0} on user Tab:

1. Create a CSV file (e.g. users.csv) with the following content:

bradley.hilton,bradley.hilton@example.com,Bradley Hilton
billy.bob, billy.bob@example.com, Billy Bob Jr.
graywolf336,graywolf336@example.com,GrayWolf336

2. Create a CSV file (e.g. channels.csv) with the following content:

"general","bradley.hilton","public",""
"otherChannelName","billy.bob","public",""
"random","bradley.hilton","public","billy.bob;graywolf336"
"privateArea","bradley.hilton","private","graywolf336"

3. Create a ZIP file containing both CSVs file you created (users.csv and channels.csv) in the previous step;

4. Go to Administration > Import > Import New File, then choose CSV as the Import Type and upload the ZIP file from your computer;

5. Click on Import. Expected behavior: 3 users and 4 channels should be displayed with all the info given in the CSV file (in different tabs);

6. Unselect all users. Expect behavior: the 'users' tab should not be disabled.

Further comments

May fix #23772 issue

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