`prospector.scanner.resend_on_touch: true` does not resend the entire file under certain conditions

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This config:

```yaml
filebeat.inputs:
- type: filestream
id: pg-hba-conf-id
prospector.scanner.resend_on_touch: true
paths:
- "/test/input/pg_hba.conf"
clean_inactive: 30s
close.on_state_change.inactive: 30s
parsers:
- multiline:
type: pattern
pattern: '^\#|^host|^local|^.*'
negate: false
match: after
flush_pattern: '^\#\#\#EOF'
max_lines: 5000
skip_newline: false

path.data: "/test/data"
logging:
level: debug
output.console:
enabled: true
```

The file content (taken from https://www.postgresql.org/docs/current/auth-pg-hba-conf.html#EXAMPLE-PG-HBA.CONF):

```
# Allow any user on the local system to connect to any database with
# any database user name using Unix-domain sockets (the default for local
# connections).
#
# TYPE DATABASE USER ADDRESS METHOD
local all all trust

# The same using local loopback TCP/IP connections.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 127.0.0.1/32 trust

# The same as the previous line, but using a separate netmask column
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host all all 127.0.0.1 255.255.255.255 trust

# The same over IPv6.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all ::1/128 trust

# The same using a host name (would typically cover both IPv4 and IPv6).
#
# TYPE DATABASE USER ADDRESS METHOD
host all all localhost trust

# Allow any user from any host with IP address 192.168.93.x to connect
# to database "postgres" as the same user name that ident reports for
# the connection (typically the operating system user name).
#
# TYPE DATABASE USER ADDRESS METHOD
host postgres all 192.168.93.0/24 ident

# Allow any user from host 192.168.12.10 to connect to database
# "postgres" if the user's password is correctly supplied.
#
# TYPE DATABASE USER ADDRESS METHOD
host postgres all 192.168.12.10/32 scram-sha-256

# Allow any user from hosts in the example.com domain to connect to
# any database if the user's password is correctly supplied.
#
# Require SCRAM authentication for most users, but make an exception
# for user 'mike', who uses an older client that doesn't support SCRAM
# authentication.
#
# TYPE DATABASE USER ADDRESS METHOD
host all mike .example.com md5
host all all .example.com scram-sha-256

# In the absence of preceding "host" lines, these three lines will
# reject all connections from 192.168.54.1 (since that entry will be
# matched first), but allow GSSAPI-encrypted connections from anywhere else
# on the Internet. The zero mask causes no bits of the host IP address to
# be considered, so it matches any host. Unencrypted GSSAPI connections
# (which "fall through" to the third line since "hostgssenc" only matches
# encrypted GSSAPI connections) are allowed, but only from 192.168.12.10.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.54.1/32 reject
hostgssenc all all 0.0.0.0/0 gss
host all all 192.168.12.10/32 gss

# Allow users from 192.168.x.x hosts to connect to any database, if
# they pass the ident check. If, for example, ident says the user is
# "bryanh" and he requests to connect as PostgreSQL user "guest1", the
# connection is allowed if there is an entry in pg_ident.conf for map
# "omicron" that says "bryanh" is allowed to connect as "guest1".
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.0.0/16 ident map=omicron

# If these are the only three lines for local connections, they will
# allow local users to connect only to their own databases (databases
# with the same name as their database user name) except for administrators
# and members of role "support", who can connect to all databases. The file
# $PGDATA/admins contains a list of names of administrators. Passwords
# are required in all cases.
#
# TYPE DATABASE USER ADDRESS METHOD
local sameuser all md5
local all @admins md5
local all +support md5

# The last two lines above can be combined into a single line:
local all @admins,+support md5

# The database column can also use lists and file names:
local db1,db2,@demodbs all
###EOF
```

Test cases:

1. Insert rows into the source file.
2. Modify a row in the source file.
3. Delete a row from the source file.
4. Insert a row/Update a row.
5. Insert a row/Delete a row.
6. Update a row/Delete a row.
7. Insert a row/Update a row/Delete a row.

In all the test cases above an event containing the entire file should be generated but instead the event message contains only the last or some random line of the file.

Start with the Filebeat filestream input, prospector scanner, and multiline parser using the YAML configuration and PostgreSQL-style fixture shown here. Reproduce the seven insert, update, and delete sequences, then verify that resend_on_touch emits an event containing the entire file rather than only a final or random line.

Written by the indexing model from the issue text.