ddl: update the error message of "modify/change column" to make it easier to understand

[zimulala]

What problem does this PR solve?

When executing "change/modify column" we encounter some error messages as follows:

create table t1 (a int(11) default null);
alter table t1 change a a varchar(16);

before this PR:

[ddl:8200]Unsupported modify charset from binary to utf8mb4

after this PR:

[ddl:8200]Unsupported modify column: type varchar(16) not match origin int(11)

Make this error message easier to understand.

What is changed and how it works?

Check the column type before checking the charset or other information.

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch

Release note

• Update the error message of "modify/change column"

[codecov]

Codecov Report

Merging #13457 into master will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master     #13457   +/-   ##
===========================================
  Coverage   80.1813%   80.1813%           
===========================================
  Files           473        473           
  Lines        117470     117470           
===========================================
  Hits          94189      94189           
  Misses        15878      15878           
  Partials       7403       7403

[zimulala]

PTAL @jackysp @bb7133 @crazycs520 @tangenta

[jackysp]

LGTM

[tangenta]

LGTM

[AilinKid]

LGTM

[sre-bot]

/run-all-tests

[sre-bot]

cherry pick to release-3.0 failed

[sre-bot]

cherry pick to release-2.1 failed

[sre-bot]

cherry pick to release-3.1 failed